diff --git a/task01/src/com/example/task01/Task01Main.java b/task01/src/com/example/task01/Task01Main.java
index de4599c1..9646ecd7 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;
 
@@ -9,13 +10,11 @@ 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);
-        */
-
     }
 
     public static <T, U> Function<T, U> ternaryOperator(
@@ -23,7 +22,9 @@ 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 x -> condition.test(x) ? ifTrue.apply(x) : ifFalse.apply(x);
     }
 }
diff --git a/task02/src/com/example/task02/Task02Main.java b/task02/src/com/example/task02/Task02Main.java
index 309260d8..aeee16c0 100644
--- a/task02/src/com/example/task02/Task02Main.java
+++ b/task02/src/com/example/task02/Task02Main.java
@@ -5,19 +5,19 @@
 public class Task02Main {
 
     public static void main(String[] args) {
-
-        /*
         cycleGrayCode(2)
                 .limit(10)
                 .forEach(System.out::println);
-        */
-
     }
 
     public static IntStream cycleGrayCode(int n) {
+        if (n < 1 || n > 16) { throw new IllegalArgumentException(); }
+        int size = 1 << n;
 
-        return null; // your implementation here
-
+        return IntStream
+                .iterate(0, i -> i + 1)
+                .map(i -> i % size)
+                .map(i -> i ^ (i >> 1));
     }
 
 }
diff --git a/task03/src/com/example/task03/Task03Main.java b/task03/src/com/example/task03/Task03Main.java
index 254d5cb0..e569a50a 100644
--- a/task03/src/com/example/task03/Task03Main.java
+++ b/task03/src/com/example/task03/Task03Main.java
@@ -21,7 +21,9 @@ public static <T> void findMinMax(
             Stream<? extends T> stream,
             Comparator<? super T> order,
             BiConsumer<? super T, ? super T> minMaxConsumer) {
+        try (Stream ){
 
-        // your implementation here
+        }
+        //return x -> stream.min(order);
     }
 }
diff --git a/task04/src/com/example/task04/Task04Main.java b/task04/src/com/example/task04/Task04Main.java
index 1e38e6eb..c0937936 100644
--- a/task04/src/com/example/task04/Task04Main.java
+++ b/task04/src/com/example/task04/Task04Main.java
@@ -1,11 +1,35 @@
 package com.example.task04;
 
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.stream.Collectors;
+
 public class Task04Main {
 
-    public static void main(String[] args) {
+    public static void main(String[] args) throws IOException {
+        try (BufferedReader reader = new BufferedReader(
+                new InputStreamReader(System.in, "UTF-8"))) {
 
-        // your implementation here
+            String text = reader.lines().collect(Collectors.joining(" "));
 
-    }
+            String result = java.util.Arrays.stream(text.split("[^\\p{L}\\d]+"))
+                    .filter(word -> !word.isEmpty())
+                    .map(String::toLowerCase)
+                    .collect(Collectors.groupingBy(w -> w, Collectors.counting()))
+                    .entrySet()
+                    .stream()
+                    .sorted(
+                            Map.Entry.<String, Long>comparingByValue().reversed()
+                                    .thenComparing(Map.Entry.comparingByKey())
+                    )
+                    .limit(10)
+                    .map(Map.Entry::getKey)
+                    .collect(Collectors.joining("\n"));
 
+            System.out.println(result);
+        }
+    }
 }
diff --git a/task05/src/com/example/task05/MailItem.java b/task05/src/com/example/task05/MailItem.java
new file mode 100644
index 00000000..90a2fe9d
--- /dev/null
+++ b/task05/src/com/example/task05/MailItem.java
@@ -0,0 +1,7 @@
+package com.example.task05;
+
+public interface MailItem <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..de23cad6
--- /dev/null
+++ b/task05/src/com/example/task05/MailMessage.java
@@ -0,0 +1,28 @@
+package com.example.task05;
+
+public class MailMessage implements MailItem<String>{
+
+    private final String from;
+    private final String to;
+    private final 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..9f5e6b46
--- /dev/null
+++ b/task05/src/com/example/task05/MailService.java
@@ -0,0 +1,31 @@
+package com.example.task05;
+
+import java.util.*;
+import java.util.function.Consumer;
+
+public class MailService<T> implements Consumer<MailItem<T>> {
+    private final Map<String, List<T>> mailBox = new HashMap<>();
+
+    @Override
+    public void accept(MailItem<T> mailItem) {
+        if (mailItem == null) return;
+        String to = mailItem.getTo();
+        T content = mailItem.getContent();
+        if (to == null || content == null) return;
+        mailBox.computeIfAbsent(to, k -> new ArrayList<>()).add(content);
+    }
+
+    public Map<String, List<T>> getMailBox() {
+        return new AbstractMap<String, List<T>>() {
+            @Override
+            public Set<Entry<String, List<T>>> entrySet() {
+                return mailBox.entrySet();
+            }
+            @Override
+            public List<T> get(Object key) {
+                List<T> list = mailBox.get(key);
+                return list != null ? list : Collections.emptyList();
+            }
+        };
+    }
+}
\ 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..677885bd
--- /dev/null
+++ b/task05/src/com/example/task05/Salary.java
@@ -0,0 +1,30 @@
+package com.example.task05;
+
+public class Salary implements MailItem<Integer> {
+
+    private final String from;
+    private final String to;
+    private final 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;
+    }
+}
diff --git a/task05/src/com/example/task05/Task05Main.java b/task05/src/com/example/task05/Task05Main.java
index ae31f6bc..f6969c1c 100644
--- a/task05/src/com/example/task05/Task05Main.java
+++ b/task05/src/com/example/task05/Task05Main.java
@@ -9,11 +9,8 @@ public class Task05Main {
 
     public static void main(String[] args) {
 
-        /*
-
-        // Random variables
-        String randomFrom = "..."; // Некоторая случайная строка. Можете выбрать ее самостоятельно.
-        String randomTo = "...";  // Некоторая случайная строка. Можете выбрать ее самостоятельно.
+        String randomFrom = "one"; // Некоторая случайная строка. Можете выбрать ее самостоятельно.
+        String randomTo = "ten";  // Некоторая случайная строка. Можете выбрать ее самостоятельно.
         int randomSalary = 100;  // Некоторое случайное целое положительное число. Можете выбрать его самостоятельно.
 
         // Создание списка из трех почтовых сообщений.
@@ -88,8 +85,6 @@ public static void main(String[] args) {
         assert salaries.get(randomTo).equals(Arrays.asList(randomSalary)) : "wrong salaries mailbox content (3)";
 
 
-        */
-
     }
 
 }