diff --git a/task01/src/com/example/task01/Task01Main.java b/task01/src/com/example/task01/Task01Main.java
index de4599c1..d5c9b023 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 || ifTrue == null || ifFalse == 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..63800b29 100644
--- a/task02/src/com/example/task02/Task02Main.java
+++ b/task02/src/com/example/task02/Task02Main.java
@@ -16,7 +16,14 @@ public static void main(String[] args) {
 
     public static IntStream cycleGrayCode(int n) {
 
-        return null; // your implementation here
+        if (n < 1 || n > 16) {
+            throw new IllegalArgumentException("Invalid bit rate.");
+        }
+
+        int size = (int) Math.pow(2, n);
+
+        return IntStream.iterate(0, code -> (code + 1) % size)
+                .map(code -> code ^ (code >> 1));
 
     }
 
diff --git a/task03/src/com/example/task03/Task03Main.java b/task03/src/com/example/task03/Task03Main.java
index 254d5cb0..42deedc2 100644
--- a/task03/src/com/example/task03/Task03Main.java
+++ b/task03/src/com/example/task03/Task03Main.java
@@ -3,6 +3,7 @@
 import java.util.Comparator;
 import java.util.function.BiConsumer;
 import java.util.stream.Stream;
+import java.util.Iterator;
 
 public class Task03Main {
 
@@ -22,6 +23,28 @@ public static <T> void findMinMax(
             Comparator<? super T> order,
             BiConsumer<? super T, ? super T> minMaxConsumer) {
 
-        // your implementation here
+        Iterator<? extends T> iterator = stream.iterator();
+
+        T minimum = null;
+        T maximum = null;
+
+        if (iterator.hasNext()) {
+            minimum = iterator.next();
+            maximum = iterator.next();
+
+            while (iterator.hasNext()) {
+                T current = iterator.next();
+
+                if (order.compare(current, minimum) < 0) {
+                    minimum = current;
+                }
+
+                if (order.compare(current, maximum) > 0) {
+                    maximum = current;
+                }
+            }
+        }
+
+        minMaxConsumer.accept(minimum, maximum);
     }
 }
diff --git a/task04/src/com/example/task04/Task04Main.java b/task04/src/com/example/task04/Task04Main.java
index 1e38e6eb..b72ba2da 100644
--- a/task04/src/com/example/task04/Task04Main.java
+++ b/task04/src/com/example/task04/Task04Main.java
@@ -1,10 +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
+        new BufferedReader(new InputStreamReader(System.in))
+                .lines()
+                .map(String::toLowerCase)
+                .filter(line -> !line.isEmpty())
+                .flatMap(line -> Stream.of(line.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.println(word.getKey()));
 
     }
 
diff --git a/task05/src/com/example/task05/Dispatchable.java b/task05/src/com/example/task05/Dispatchable.java
new file mode 100644
index 00000000..87412b8b
--- /dev/null
+++ b/task05/src/com/example/task05/Dispatchable.java
@@ -0,0 +1,7 @@
+package com.example.task05;
+
+public interface Dispatchable<T> {
+    String getTo();
+    String getFrom();
+    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..32c60785
--- /dev/null
+++ b/task05/src/com/example/task05/MailMessage.java
@@ -0,0 +1,28 @@
+package com.example.task05;
+
+public class MailMessage implements Dispatchable<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 getTo() {
+        return to;
+    }
+
+    @Override
+    public String getFrom() {
+        return from;
+    }
+
+    @Override
+    public String getContent() {
+        return content;
+    }
+}
diff --git a/task05/src/com/example/task05/MailService.java b/task05/src/com/example/task05/MailService.java
new file mode 100644
index 00000000..6aace12a
--- /dev/null
+++ b/task05/src/com/example/task05/MailService.java
@@ -0,0 +1,25 @@
+package com.example.task05;
+
+import java.util.*;
+import java.util.function.Consumer;
+
+public class MailService<T> implements Consumer<Dispatchable<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());
+        }
+    };
+
+    @Override
+    public void accept(Dispatchable<T> mail) {
+        mailBox
+                .computeIfAbsent(mail.getTo(), key -> new ArrayList<>())
+                .add(mail.getContent());
+    }
+
+    public Map<String, List<T>> getMailBox() {
+        return mailBox;
+    }
+}
diff --git a/task05/src/com/example/task05/Salary.java b/task05/src/com/example/task05/Salary.java
new file mode 100644
index 00000000..7b266774
--- /dev/null
+++ b/task05/src/com/example/task05/Salary.java
@@ -0,0 +1,28 @@
+package com.example.task05;
+
+public class Salary implements Dispatchable<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 getTo() {
+        return to;
+    }
+
+    @Override
+    public String getFrom() {
+        return from;
+    }
+
+    @Override
+    public Integer getContent() {
+        return amount;
+    }
+}
diff --git a/task05/src/com/example/task05/Task05Main.java b/task05/src/com/example/task05/Task05Main.java
index ae31f6bc..065eadf3 100644
--- a/task05/src/com/example/task05/Task05Main.java
+++ b/task05/src/com/example/task05/Task05Main.java
@@ -9,7 +9,7 @@ public class Task05Main {
 
     public static void main(String[] args) {
 
-        /*
+
 
         // Random variables
         String randomFrom = "..."; // Некоторая случайная строка. Можете выбрать ее самостоятельно.
@@ -88,7 +88,7 @@ public static void main(String[] args) {
         assert salaries.get(randomTo).equals(Arrays.asList(randomSalary)) : "wrong salaries mailbox content (3)";
 
 
-        */
+
 
     }