import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[][] c = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }
        int a = c[0][0] + c[1][1] + c[2][2];
        int b = c[0][1] + c[1][2] + c[2][0];
        int d = c[0][2] + c[1][0] + c[2][1];
        if (a == b && b == d)
            System.out.println("Yes");
        else
            System.out.println("No");
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[][] c = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }
        int a = c[0][0] + c[1][1] + c[2][2];
        int b = c[0][1] + c[1][2] + c[2][0];
        int d = c[0][2] + c[1][0] + c[2][1];
        if (a == b && b == d)
            System.out.println("Yes");
        else
            System.out.println("No");
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[][] c = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }
        int a = c[0][0] + c[1][1] + c[2][2];
        int b = c[0][1] + c[1][2] + c[2][0];
        int d = c[0][2] + c[1][0] + c[2][1];
        if (a == b && b == d)
            System.out.println("Yes");
        else
            System.out.println("No");
    } main {
        Scanner sc = new Scanner(System.in);
        int[][] c = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }
        int a = c[0][0] + c[1][1] + c[2][2];
        int b = c[0][1] + c[1][2] + c[2][0];
        int d = c[0][2] + c[1][0] + c[2][1];
        if (a == b && b == d)
            System.out.println("Yes");
        else
            System.out.println("No");
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[][] c = new int[3][3]; c new int[3][3] 3 3 for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        } 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] = sc.nextInt();
            }
        } {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        } for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                c[i][j] = sc.nextInt();
            } {
                c[i][j] = sc.nextInt();
            } c[i][j] = sc.nextInt() c[i][j] c[i] c i j sc.nextInt() sc.nextInt sc int a = c[0][0] + c[1][1] + c[2][2]; a 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 int b = c[0][1] + c[1][2] + c[2][0]; b c[0][1] + c[1][2] + c[2][0] c[0][1] + c[1][2] + c[2][0] c[0][1] c[0] c 0 1 c[1][2] c[1] c 1 2 c[2][0] c[2] c 2 0 int d = c[0][2] + c[1][0] + c[2][1]; d c[0][2] + c[1][0] + c[2][1] c[0][2] + c[1][0] + c[2][1] c[0][2] c[0] c 0 2 c[1][0] c[1] c 1 0 c[2][1] c[2] c 2 1 if (a == b && b == d)
            System.out.println("Yes");
        else
            System.out.println("No"); a == b && b == d a == b a b b == d b d System.out.println("Yes") System.out.println System.out System System.out "Yes" 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 sc = new Scanner(System.in);
        int[][] c = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }
        int a = c[0][0] + c[1][1] + c[2][2];
        int b = c[0][1] + c[1][2] + c[2][0];
        int d = c[0][2] + c[1][0] + c[2][1];
        if (a == b && b == d)
            System.out.println("Yes");
        else
            System.out.println("No");
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[][] c = new int[3][3];
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }
        int a = c[0][0] + c[1][1] + c[2][2];
        int b = c[0][1] + c[1][2] + c[2][0];
        int d = c[0][2] + c[1][0] + c[2][1];
        if (a == b && b == d)
            System.out.println("Yes");
        else
            System.out.println("No");
    }
} Main
import java.util.*;

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