import java.util.Scanner;

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();
        }
        
        boolean isOK = true;
        isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]);
        isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]);
        isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]);
        isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]);

        String ans = isOK ? "Yes" : "No";
        System.out.println(ans);
    }
} import java.util.Scanner; Scanner 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();
        }
        
        boolean isOK = true;
        isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]);
        isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]);
        isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]);
        isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]);

        String ans = isOK ? "Yes" : "No";
        System.out.println(ans);
    }
} 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();
        }
        
        boolean isOK = true;
        isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]);
        isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]);
        isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]);
        isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]);

        String ans = isOK ? "Yes" : "No";
        System.out.println(ans);
    } 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();
        }
        
        boolean isOK = true;
        isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]);
        isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]);
        isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]);
        isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]);

        String ans = isOK ? "Yes" : "No";
        System.out.println(ans);
    } 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] c[i] c i j sc.nextInt() sc.nextInt sc boolean isOK = true; isOK true isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]) isOK (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]) (c[0][0] - c[0][1]) c[0][0] c[0] c 0 0 c[0][1] c[0] c 0 1 (c[1][0] - c[1][1]) c[1][0] c[1] c 1 0 c[1][1] c[1] c 1 1 isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]) isOK (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]) (c[0][0] - c[0][1]) c[0][0] c[0] c 0 0 c[0][1] c[0] c 0 1 (c[2][0] - c[2][1]) c[2][0] c[2] c 2 0 c[2][1] c[2] c 2 1 isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]) isOK (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]) (c[1][0] - c[1][1]) c[1][0] c[1] c 1 0 c[1][1] c[1] c 1 1 (c[2][0] - c[2][1]) c[2][0] c[2] c 2 0 c[2][1] c[2] c 2 1 isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]) isOK (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]) (c[0][0] - c[0][2]) c[0][0] c[0] c 0 0 c[0][2] c[0] c 0 2 (c[1][0] - c[1][2]) c[1][0] c[1] c 1 0 c[1][2] c[1] c 1 2 isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]) isOK (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]) (c[0][0] - c[0][2]) c[0][0] c[0] c 0 0 c[0][2] c[0] c 0 2 (c[2][0] - c[2][2]) c[2][0] c[2] c 2 0 c[2][2] c[2] c 2 2 isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]) isOK (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]) (c[1][0] - c[1][2]) c[1][0] c[1] c 1 0 c[1][2] c[1] c 1 2 (c[2][0] - c[2][2]) c[2][0] c[2] c 2 0 c[2][2] c[2] c 2 2 isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]) isOK (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]) (c[0][1] - c[0][2]) c[0][1] c[0] c 0 1 c[0][2] c[0] c 0 2 (c[1][1] - c[1][2]) c[1][1] c[1] c 1 1 c[1][2] c[1] c 1 2 isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]) isOK (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]) (c[0][1] - c[0][2]) c[0][1] c[0] c 0 1 c[0][2] c[0] c 0 2 (c[2][1] - c[2][2]) c[2][1] c[2] c 2 1 c[2][2] c[2] c 2 2 isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]) isOK (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]) (c[1][1] - c[1][2]) c[1][1] c[1] c 1 1 c[1][2] c[1] c 1 2 (c[2][1] - c[2][2]) c[2][1] c[2] c 2 1 c[2][2] c[2] c 2 2 String ans = isOK ? "Yes" : "No"; ans isOK ? "Yes" : "No" isOK "Yes" "No" System.out.println(ans) System.out.println System.out System System.out ans 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();
        }
        
        boolean isOK = true;
        isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]);
        isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]);
        isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]);
        isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]);

        String ans = isOK ? "Yes" : "No";
        System.out.println(ans);
    }
} 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();
        }
        
        boolean isOK = true;
        isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]);
        isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]);
        isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]);
        isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]);

        String ans = isOK ? "Yes" : "No";
        System.out.println(ans);
    }
} Main
import java.util.Scanner;

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();
        }
        
        boolean isOK = true;
        isOK &= (c[0][0] - c[0][1]) == (c[1][0] - c[1][1]);
        isOK &= (c[0][0] - c[0][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[1][0] - c[1][1]) == (c[2][0] - c[2][1]);
        isOK &= (c[0][0] - c[0][2]) == (c[1][0] - c[1][2]);
        isOK &= (c[0][0] - c[0][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[1][0] - c[1][2]) == (c[2][0] - c[2][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[1][1] - c[1][2]);
        isOK &= (c[0][1] - c[0][2]) == (c[2][1] - c[2][2]);
        isOK &= (c[1][1] - c[1][2]) == (c[2][1] - c[2][2]);

        String ans = isOK ? "Yes" : "No";
        System.out.println(ans);
    }
}
