import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int c[][] = new int[3][3];
        int sum = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        }
        if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }

    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int c[][] = new int[3][3];
        int sum = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        }
        if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }

    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int c[][] = new int[3][3];
        int sum = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        }
        if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }

    } main {
        Scanner scanner = new Scanner(System.in);
        int c[][] = new int[3][3];
        int sum = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        }
        if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }

    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int c[][] = new int[3][3]; c new int[3][3] 3 3 int sum = 0; sum 0 for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        } int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        } {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        } for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            } {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            } c[i][j] = scanner.nextInt() c[i][j] c[i] c i j scanner.nextInt() scanner.nextInt scanner sum += c[i][j] sum c[i][j] c[i] c i j if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        } sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2] sum % 3 == 0 sum % 3 sum 3 0 sum / 3 == c[0][0] + c[1][1] + c[2][2] sum / 3 sum 3 c[0][0] + c[1][1] + c[2][2] c[0][0] + c[1][1] + c[2][2] c[0][0] c[0] c 0 0 c[1][1] c[1] c 1 1 c[2][2] c[2] c 2 2 {
            System.out.println("Yes");
        } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
            System.out.println("No");
        } System.out.println("No") System.out.println System.out System System.out "No" String[] args args public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int c[][] = new int[3][3];
        int sum = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        }
        if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }

    }
} public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int c[][] = new int[3][3];
        int sum = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        }
        if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }

    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int c[][] = new int[3][3];
        int sum = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = scanner.nextInt();
                sum += c[i][j];
            }
        }
        if (sum % 3 == 0 && sum / 3 == c[0][0] + c[1][1] + c[2][2]) {
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }

    }
}
