diff --git a/HTTPCalculator/build.gradle b/HTTPCalculator/build.gradle
new file mode 100644
index 0000000..ebdd290
--- /dev/null
+++ b/HTTPCalculator/build.gradle
@@ -0,0 +1,21 @@
+plugins {
+    id 'org.jetbrains.kotlin.jvm' version '1.3.21'
+}
+
+group 'ru.hse.dkaznacheev'
+version '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+}
+
+compileKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+compileTestKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
\ No newline at end of file
diff --git a/HTTPCalculator/gradle.properties b/HTTPCalculator/gradle.properties
new file mode 100644
index 0000000..29e08e8
--- /dev/null
+++ b/HTTPCalculator/gradle.properties
@@ -0,0 +1 @@
+kotlin.code.style=official
\ No newline at end of file
diff --git a/HTTPCalculator/gradle/wrapper/gradle-wrapper.jar b/HTTPCalculator/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..01b8bf6
Binary files /dev/null and b/HTTPCalculator/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/HTTPCalculator/gradle/wrapper/gradle-wrapper.properties b/HTTPCalculator/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..933b647
--- /dev/null
+++ b/HTTPCalculator/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip
diff --git a/HTTPCalculator/gradlew b/HTTPCalculator/gradlew
new file mode 100755
index 0000000..cccdd3d
--- /dev/null
+++ b/HTTPCalculator/gradlew
@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"
diff --git a/HTTPCalculator/gradlew.bat b/HTTPCalculator/gradlew.bat
new file mode 100644
index 0000000..f955316
--- /dev/null
+++ b/HTTPCalculator/gradlew.bat
@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/HTTPCalculator/settings.gradle b/HTTPCalculator/settings.gradle
new file mode 100644
index 0000000..6e71a7a
--- /dev/null
+++ b/HTTPCalculator/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'HTTPCalculator'
+
diff --git a/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Calculation.kt b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Calculation.kt
new file mode 100644
index 0000000..a69d98a
--- /dev/null
+++ b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Calculation.kt
@@ -0,0 +1,112 @@
+package ru.hse.dkaznacheev.httpcalculator
+
+import java.net.URLEncoder
+import kotlin.math.roundToLong
+
+data class Calculation(val lhs: Long, val rhs: Long?, val operation: String) {
+
+    fun toURL(): String {
+        val builder = StringBuilder()
+        builder.append("/calc?")
+        builder.append("lhs=$lhs")
+        if (rhs != null) {
+            builder.append("&rhs=$rhs")
+        }
+        builder.append("&op=${URLEncoder.encode(operation, "utf-8")}")
+        return builder.toString()
+    }
+
+    fun evaluate(): Long? {
+        if (operation in quickOperations) {
+            if (rhs == null)
+                return null
+            return when(operation) {
+                "+" -> lhs + rhs
+                "-" -> lhs - rhs
+                "/" -> if (rhs == 0.toLong()) null else lhs / rhs
+                "*" -> lhs * rhs
+                else -> null
+            }
+        }
+
+        if (operation == "fact") {
+            return (1..lhs).reduce { acc, arg -> acc * arg }
+        }
+
+        if (operation == "sqrt") {
+            return Math.sqrt(lhs.toDouble()).roundToLong()
+        }
+
+        return null
+    }
+
+    fun isLong(): Boolean {
+        return operation in longOperations
+    }
+
+    companion object {
+        private val longOperations = listOf("sqrt", "fact")
+        private val quickOperations = listOf("+", "-", '*', "/")
+        private val availableOperations = longOperations.plus(quickOperations)
+
+        fun parseCalculationfromURL(url: String): Calculation? {
+            val urlParts = url.split("?")
+
+            if (urlParts.size < 2 || urlParts[0] != "/calc")
+                return null
+
+            val params = urlParts[1].split("&")
+
+            var lhs: Long? = null
+            var rhs: Long? = null
+            var operation: String? = null
+
+            for (param in params) {
+                val paramParts = param.split("=")
+                if (paramParts.size < 2)
+                    return null
+                when (paramParts[0]) {
+                    "lhs" -> lhs = paramParts[1].toLongOrNull() ?: return null
+                    "rhs" -> rhs = paramParts[1].toLongOrNull() ?: return null
+                    "op" -> operation = paramParts[1]
+                }
+            }
+
+            if (lhs == null || operation == null)
+                return null
+
+            if (operation !in availableOperations)
+                return null
+
+            return Calculation(lhs, rhs, operation)
+        }
+
+        private fun parseOneArgCalculation(line: String, operation: String): Calculation? {
+            val lhs = line.drop(operation.length + 1).toLongOrNull() ?: return null
+            return Calculation(lhs, null, operation)
+        }
+
+        private fun parseTwoArgCalculation(line: String): Calculation? {
+            val tokens = line.split(" ")
+            if (tokens.size != 3)
+                return null
+            val lhs = tokens[0].toLongOrNull() ?: return null
+            val operation = tokens[1]
+            val rhs = tokens[2].toLongOrNull() ?: return null
+
+            return Calculation(lhs, rhs, operation)
+        }
+
+        fun parseCalculationFromLine(line: String): Calculation? {
+            if (line.startsWith("fact ")) {
+                return parseOneArgCalculation(line, "fact")
+            }
+            if (line.startsWith("sqrt ")) {
+                return parseOneArgCalculation(line, "sqrt")
+
+            }
+
+            return parseTwoArgCalculation(line)
+        }
+    }
+}
\ No newline at end of file
diff --git a/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Client.kt b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Client.kt
new file mode 100644
index 0000000..dc90d85
--- /dev/null
+++ b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Client.kt
@@ -0,0 +1,70 @@
+package ru.hse.dkaznacheev.httpcalculator
+
+import ru.hse.dkaznacheev.httpcalculator.Calculation.Companion.parseCalculationFromLine
+import ru.hse.dkaznacheev.httpcalculator.HTTPService.receiveMessage
+import ru.hse.dkaznacheev.httpcalculator.HTTPService.resultCode
+import ru.hse.dkaznacheev.httpcalculator.HTTPService.sendGetRequest
+import java.net.ConnectException
+import java.net.Socket
+import java.net.SocketException
+
+class Client(address: String, port: Int) {
+    private val socket = Socket(address, port)
+    private val reader = socket.getInputStream().bufferedReader()
+    private val writer = socket.getOutputStream().bufferedWriter()
+
+    private fun receiveResults() {
+        while (!socket.isClosed) {
+            try {
+                val response = receiveMessage(reader)
+                if (response == null) {
+                    println("Error receiving response")
+                    continue
+                }
+                when (resultCode(response.requestLine)) {
+                    "200" -> println(response.body)
+                    "400" -> println("Incorrect request")
+                    "409" -> println("Error: ${response.body}")
+                }
+            } catch (e: SocketException) {
+                println("Connection closed")
+                return
+            }
+        }
+    }
+
+    fun start() {
+        println("Connected to server!")
+        Thread {receiveResults()}.start()
+        while (true) {
+            val line = readLine()
+            if (line == null || line == "exit") {
+                socket.close()
+                return
+            }
+            val calculation = parseCalculationFromLine(line)
+            if (calculation == null) {
+                println("Incorrect input")
+                continue
+            }
+            val url = calculation.toURL()
+            sendGetRequest(url, writer)
+        }
+    }
+}
+
+fun main(args: Array<String>) {
+    if (args.size < 2) {
+        println("Incorrect argument size")
+        return
+    }
+
+    val address = args[0]
+    val port = args[1].toInt()
+
+    try {
+        Client(address, port).start()
+    } catch (e: ConnectException) {
+        println("Error connecting $address/$port")
+    }
+}
\ No newline at end of file
diff --git a/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/HTTPMessage.kt b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/HTTPMessage.kt
new file mode 100644
index 0000000..3235dac
--- /dev/null
+++ b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/HTTPMessage.kt
@@ -0,0 +1,29 @@
+package ru.hse.dkaznacheev.httpcalculator
+
+import java.net.URLDecoder
+import java.util.LinkedHashMap
+
+data class HTTPMessage(val requestLine: String, val headers: LinkedHashMap<String, String>, val body: String) {
+    val requestType: String
+    val url: String
+
+    init {
+        val tokens = requestLine.split(" ")
+        requestType = tokens[0]
+        url = URLDecoder.decode(tokens[1], getCharset() ?: "utf-8")
+    }
+
+    override fun toString(): String {
+        val headersString = headers.toList().joinToString("\n") { "${it.first}: ${it.second}" }
+        return requestLine + "\n" + headersString + "\n" + body
+    }
+
+    private fun getCharset(): String? {
+        val contentType = headers["Content-type"] ?: return null
+        val tokens = contentType.split("; ")
+
+        return tokens
+            .find { it.startsWith("charset=") }
+            ?.substring("charset=".length)
+    }
+}
\ No newline at end of file
diff --git a/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/HTTPService.kt b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/HTTPService.kt
new file mode 100644
index 0000000..cabdfcc
--- /dev/null
+++ b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/HTTPService.kt
@@ -0,0 +1,78 @@
+package ru.hse.dkaznacheev.httpcalculator
+
+import java.io.BufferedReader
+import java.io.BufferedWriter
+import java.net.SocketException
+
+object HTTPService {
+
+    fun receiveMessage(reader: BufferedReader): HTTPMessage? {
+        var line: String
+        val headers = LinkedHashMap<String, String>()
+
+        val requestLine = reader.readLine() ?: throw SocketException()
+        while (true) {
+            line = reader.readLine()
+            if (line == "")
+                break
+            val parts = line.split(": ")
+            if (parts.size < 2)
+                return null
+            headers[parts[0]] = parts.drop(1).joinToString()
+        }
+        if ("Content-Length" in headers) {
+            val length = headers["Content-Length"]!!.toInt()
+            val buffer = CharArray(length)
+            reader.read(buffer, 0, length)
+            return HTTPMessage(requestLine, headers, buffer.joinToString(""))
+        }
+        println(HTTPMessage(requestLine, headers, ""))
+        return HTTPMessage(requestLine, headers, "")
+    }
+
+    private fun respond(statusCode: String, body: String, writer: BufferedWriter) {
+        val outWriter = System.out.bufferedWriter()
+        outWriter.write("HTTP/1.1 $statusCode\n")
+        outWriter.write(
+            "Content-Type: text/plain; charset=utf-8\n" +
+                    "Server: calculator/1.0\n" +
+                    "Content-Length: ${body.length}\n")
+        outWriter.write("\n")
+        outWriter.write(body)
+        outWriter.flush()
+
+        writer.write("HTTP/1.1 $statusCode\n")
+        writer.write(
+            "Content-Type: text/plain; charset=utf-8\n" +
+            "Server: calculator/1.0\n" +
+            "Content-Length: ${body.length}\n")
+        writer.write("\n")
+        writer.write(body)
+        writer.flush()
+    }
+
+    fun respondBadRequest(writer: BufferedWriter) {
+        respond("400 Bad Request Error", "", writer)
+    }
+
+    fun respondBadCalculation(writer: BufferedWriter) {
+        respond("409 Conflict", "Division by zero", writer)
+    }
+
+    fun respondSuccessfulCalculation(result: Long, writer: BufferedWriter) {
+        respond("200 OK", "$result\n", writer)
+    }
+
+    fun sendGetRequest(url: String, writer: BufferedWriter) {
+        writer.write("GET $url HTTP/1.1\n")
+        writer.write("User-Agent: calculator/1.0\n")
+        writer.write("Accept: */*\n")
+        writer.newLine()
+        writer.flush()
+    }
+
+    fun resultCode(line: String): String {
+        val tokens = line.split(" ")
+        return tokens[1]
+    }
+}
\ No newline at end of file
diff --git a/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Server.kt b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Server.kt
new file mode 100644
index 0000000..b6f0f30
--- /dev/null
+++ b/HTTPCalculator/src/main/kotlin/ru/hse/dkaznacheev/httpcalculator/Server.kt
@@ -0,0 +1,66 @@
+package ru.hse.dkaznacheev.httpcalculator
+
+import ru.hse.dkaznacheev.httpcalculator.Calculation.Companion.parseCalculationfromURL
+import ru.hse.dkaznacheev.httpcalculator.HTTPService.receiveMessage
+import ru.hse.dkaznacheev.httpcalculator.HTTPService.respondBadCalculation
+import ru.hse.dkaznacheev.httpcalculator.HTTPService.respondBadRequest
+import ru.hse.dkaznacheev.httpcalculator.HTTPService.respondSuccessfulCalculation
+import java.io.BufferedWriter
+import java.net.ServerSocket
+import java.net.Socket
+import java.net.SocketException
+
+class Server(port: Int) {
+    private val server = ServerSocket(port)
+
+    private fun processCalculation(calculation: Calculation, writer: BufferedWriter) {
+        val result = calculation.evaluate()
+        if (result == null) {
+            respondBadCalculation(writer)
+        } else {
+            respondSuccessfulCalculation(result, writer)
+        }
+    }
+
+    private fun clientHandler(socket: Socket) {
+        while (true) {
+            try {
+                val writer = socket.getOutputStream().bufferedWriter()
+                val request = receiveMessage(socket.getInputStream().bufferedReader())
+
+                if (request == null) {
+                    respondBadRequest(writer)
+                    return
+                }
+
+                val calculation = parseCalculationfromURL(request.url)
+
+                if (calculation == null) {
+                    respondBadRequest(writer)
+                    return
+                }
+
+                if (!calculation.isLong()) {
+                    processCalculation(calculation, writer)
+                } else {
+                    Thread { processCalculation(calculation, writer) }.start()
+                }
+            } catch (e: SocketException) {
+                socket.close()
+                println("Client disconnected")
+                return
+            }
+        }
+    }
+
+    fun start() {
+        while (true) {
+            val socket = server.accept()
+            Thread {clientHandler(socket)}.start()
+        }
+    }
+}
+
+fun main() {
+    Server(8000).start()
+}
\ No newline at end of file