diff --git a/app/src/main/java/ru/project/student/Student.java b/app/src/main/java/ru/project/student/Student.java
index 156059d..9dc74e2 100644
--- a/app/src/main/java/ru/project/student/Student.java
+++ b/app/src/main/java/ru/project/student/Student.java
@@ -5,23 +5,26 @@ import java.util.Objects;
 public class Student {
     private final String groupNumber;
     private final double averageGrade;
-    private final String recordBookNumber;
+    private final int recordBookNumber;
 
-    Student(String groupNumber, double averageGrade, String recordBookNumber) {
-        if (groupNumber == null || groupNumber.isBlank()) {
-            throw new IllegalArgumentException("Group number cannot be empty");
+    // Конструктор с проверками
+    public Student(String groupNumber, double averageGrade, int recordBookNumber) {
+        // Проверка groupNumber на формат
+        if (groupNumber == null || !groupNumber.matches("^[A-Z][0-9]{2}$")) {
+            throw new IllegalArgumentException("Group number must match format: one uppercase letter + two digits (e.g. A12)");
         }
         if (averageGrade < 0.0 || averageGrade > 5.0) {
             throw new IllegalArgumentException("Average grade must be between 0.0 and 5.0");
         }
-        if (recordBookNumber == null || recordBookNumber.isBlank()) {
-            throw new IllegalArgumentException("Record book number cannot be empty");
+        if (recordBookNumber <= 0) {
+            throw new IllegalArgumentException("Record book number must be positive");
         }
         this.groupNumber = groupNumber;
         this.averageGrade = averageGrade;
         this.recordBookNumber = recordBookNumber;
     }
 
+    // Геттеры — исправлен тип groupNumber (теперь String)
     public String getGroupNumber() {
         return groupNumber;
     }
@@ -30,38 +33,40 @@ public class Student {
         return averageGrade;
     }
 
-    public String getRecordBookNumber() {
+    public int getRecordBookNumber() {
         return recordBookNumber;
     }
 
+    // Методы копирования (with-методы)
+    public Student withGroupNumber(String groupNumber) {
+        return new Student(groupNumber, this.averageGrade, this.recordBookNumber);
+    }
+
+    public Student withAverageGrade(double averageGrade) {
+        return new Student(this.groupNumber, averageGrade, this.recordBookNumber);
+    }
+
+    public Student withRecordBookNumber(int recordBookNumber) {
+        return new Student(this.groupNumber, this.averageGrade, recordBookNumber);
+    }
+
     @Override
     public String toString() {
         return "Student{" +
                 "groupNumber='" + groupNumber + '\'' +
                 ", averageGrade=" + averageGrade +
-                ", recordBookNumber='" + recordBookNumber + '\'' +
+                ", recordBookNumber=" + recordBookNumber +
                 '}';
     }
 
     @Override
     public boolean equals(Object obj) {
-        if (this == obj) {
-            return true;
-        }
-
-        if (obj == null || getClass() != obj.getClass()) {
-            return false;
-        }
-
-        if (this.hashCode() != obj.hashCode()) {
-            return false;
-        }
-
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
         Student student = (Student) obj;
-
         return Double.compare(averageGrade, student.averageGrade) == 0
-                && Objects.equals(groupNumber, student.groupNumber)
-                && Objects.equals(recordBookNumber, student.recordBookNumber);
+                && recordBookNumber == student.recordBookNumber
+                && Objects.equals(groupNumber, student.groupNumber);
     }
 
     @Override
diff --git a/app/src/main/java/ru/project/student/StudentBuilder.java b/app/src/main/java/ru/project/student/StudentBuilder.java
index 3e1ec41..6d7d5fc 100644
--- a/app/src/main/java/ru/project/student/StudentBuilder.java
+++ b/app/src/main/java/ru/project/student/StudentBuilder.java
@@ -3,7 +3,7 @@ package ru.project.student;
 public class StudentBuilder {
     private String groupNumber;
     private double averageGrade;
-    private String recordBookNumber;
+    private int recordBookNumber;
 
     public StudentBuilder setGroupNumber(String groupNumber) {
         this.groupNumber = groupNumber;
@@ -15,7 +15,7 @@ public class StudentBuilder {
         return this;
     }
 
-    public StudentBuilder setRecordBookNumber(String recordBookNumber) {
+    public StudentBuilder setRecordBookNumber(int recordBookNumber) {
         this.recordBookNumber = recordBookNumber;
         return this;
     }
@@ -23,4 +23,4 @@ public class StudentBuilder {
     public Student build() {
         return new Student(groupNumber, averageGrade, recordBookNumber);
     }
-}
\ No newline at end of file
+}