diff --git a/task01/src/com/example/task01/Task01Main.java b/task01/src/com/example/task01/Task01Main.java
index de4599c1..77ff708d 100644
--- a/task01/src/com/example/task01/Task01Main.java
+++ b/task01/src/com/example/task01/Task01Main.java
@@ -1,6 +1,7 @@
 package com.example.task01;
 
 import java.io.IOException;
+import java.util.Objects;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
@@ -9,12 +10,12 @@ public static void main(String[] args) throws IOException {
 
         // TODO С корректно реализованным методом ternaryOperator должен компилироваться и успешно работать следующий код:
 
-        /*
+
         Predicate<Object> condition = Objects::isNull;
         Function<Object, Integer> ifTrue = obj -> 0;
         Function<CharSequence, Integer> ifFalse = CharSequence::length;
         Function<String, Integer> safeStringLength = ternaryOperator(condition, ifTrue, ifFalse);
-        */
+
 
     }
 
@@ -23,7 +24,17 @@ public static <T, U> Function<T, U> ternaryOperator(
             Function<? super T, ? extends U> ifTrue,
             Function<? super T, ? extends U> ifFalse) {
 
-        return null; // your implementation here
-
+        if(condition == null || ifFalse == null || ifTrue == null){
+            throw new NullPointerException();
+        }
+
+        return input -> {
+            if(condition.test(input)){
+                return ifTrue.apply(input);
+            }
+            else{
+                return ifFalse.apply(input);
+            }
+        };
     }
 }
diff --git a/task02/src/com/example/task02/Task02Main.java b/task02/src/com/example/task02/Task02Main.java
index 309260d8..4f84ffcb 100644
--- a/task02/src/com/example/task02/Task02Main.java
+++ b/task02/src/com/example/task02/Task02Main.java
@@ -6,17 +6,22 @@ public class Task02Main {
 
     public static void main(String[] args) {
 
-        /*
+
         cycleGrayCode(2)
                 .limit(10)
                 .forEach(System.out::println);
-        */
+
 
     }
 
     public static IntStream cycleGrayCode(int n) {
 
-        return null; // your implementation here
+        if(n < 1 || n > 16){
+            throw new IllegalArgumentException();
+        }
+
+        return IntStream.iterate(0, x -> (x + 1) % (int) Math.pow(2, n))
+                .map(x -> x ^ (x >> 1));
 
     }
 
diff --git a/task03/src/com/example/task03/Task03Main.java b/task03/src/com/example/task03/Task03Main.java
index 254d5cb0..600928f1 100644
--- a/task03/src/com/example/task03/Task03Main.java
+++ b/task03/src/com/example/task03/Task03Main.java
@@ -1,5 +1,6 @@
 package com.example.task03;
 
+import java.util.Iterator;
 import java.util.Comparator;
 import java.util.function.BiConsumer;
 import java.util.stream.Stream;
@@ -22,6 +23,24 @@ public static <T> void findMinMax(
             Comparator<? super T> order,
             BiConsumer<? super T, ? super T> minMaxConsumer) {
 
-        // your implementation here
+        Iterator<? extends T> iterator = stream.iterator();
+
+        if(!iterator.hasNext()){
+            minMaxConsumer.accept(null, null);
+        }
+        else{
+            T min = iterator.next();
+            T max = min;
+            while(iterator.hasNext()){
+                T currentElem = iterator.next();
+                if(order.compare(currentElem, min) < 0){
+                    min = currentElem;
+                }
+                else if (order.compare(currentElem, max) > 0) {
+                    max = currentElem;
+                }
+            }
+            minMaxConsumer.accept(min, max);
+        }
     }
 }
diff --git a/task04/src/com/example/task04/Task04Main.java b/task04/src/com/example/task04/Task04Main.java
index 1e38e6eb..f9c2ac9a 100644
--- a/task04/src/com/example/task04/Task04Main.java
+++ b/task04/src/com/example/task04/Task04Main.java
@@ -1,11 +1,29 @@
 package com.example.task04;
 
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
 public class Task04Main {
 
     public static void main(String[] args) {
 
-        // your implementation here
+        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+        reader.lines()
+                .map(String::toLowerCase)
+                .filter(x -> !x.isEmpty())
+                .flatMap(x -> Stream.of(x.split("[\\p{Punct}\\s]+")))
+                .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()))
+                .entrySet()
+                .stream()
+                .sorted(Map.Entry.comparingByKey())
+                .sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
+                .limit(10)
+                .forEach(word -> System.out.print(word.getKey() + "\n"));
 
     }
-
 }
diff --git a/task05/src/com/example/task05/IMail.java b/task05/src/com/example/task05/IMail.java
new file mode 100644
index 00000000..3d020d85
--- /dev/null
+++ b/task05/src/com/example/task05/IMail.java
@@ -0,0 +1,7 @@
+package com.example.task05;
+
+public interface IMail<T> {
+    String getFrom();
+    String getTo();
+    T getContent();
+}
diff --git a/task05/src/com/example/task05/MailMessage.java b/task05/src/com/example/task05/MailMessage.java
new file mode 100644
index 00000000..e89646c1
--- /dev/null
+++ b/task05/src/com/example/task05/MailMessage.java
@@ -0,0 +1,28 @@
+package com.example.task05;
+
+public class MailMessage implements IMail<String>{
+    final private String from;
+    final private String to;
+    final private String content;
+
+    public MailMessage(String from, String to, String content){
+        this.from = from;
+        this.to = to;
+        this.content = content;
+    }
+
+    @Override
+    public String getFrom(){
+        return from;
+    }
+
+    @Override
+    public String getTo(){
+        return to;
+    }
+
+    @Override
+    public String getContent(){
+        return content;
+    }
+}
\ No newline at end of file
diff --git a/task05/src/com/example/task05/MailService.java b/task05/src/com/example/task05/MailService.java
new file mode 100644
index 00000000..7ec8b0c1
--- /dev/null
+++ b/task05/src/com/example/task05/MailService.java
@@ -0,0 +1,22 @@
+package com.example.task05;
+import java.util.*;
+import java.util.function.Consumer;
+
+public class MailService <T> implements Consumer<IMail<T>> {
+
+    private final Map<String, List<T>> mailBox = new HashMap<String, List<T>>() {
+        @Override
+        public List<T> get(Object key) {
+            return super.getOrDefault(key, Collections.emptyList());
+        }
+    };
+
+    public void accept(IMail<T> mail){
+        mailBox.computeIfAbsent(mail.getTo(), key -> new ArrayList<>())
+                .add(mail.getContent());
+    }
+
+    public Map<String, List<T>> getMailBox() {
+        return mailBox;
+    }
+}
\ No newline at end of file
diff --git a/task05/src/com/example/task05/Salary.java b/task05/src/com/example/task05/Salary.java
new file mode 100644
index 00000000..daf5929e
--- /dev/null
+++ b/task05/src/com/example/task05/Salary.java
@@ -0,0 +1,28 @@
+package com.example.task05;
+
+public class Salary implements IMail<Integer> {
+    final private String from;
+    final private String to;
+    final private Integer amount;
+
+    public Salary(String from, String to, Integer amount){
+        this.from = from;
+        this.to = to;
+        this.amount = amount;
+    }
+
+    @Override
+    public String getFrom(){
+        return from;
+    }
+
+    @Override
+    public String getTo(){
+        return to;
+    }
+
+    @Override
+    public Integer getContent(){
+        return amount;
+    }
+}
\ No newline at end of file