import java.util.*;

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 flag = false;
        if(c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2])
            flag = true;

        if(flag) System.out.println("Yes");
        else System.out.println("No");
          
    }
} import java.util.*; util.* java 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 flag = false;
        if(c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2])
            flag = true;

        if(flag) 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();
            }
        }

        boolean flag = false;
        if(c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2])
            flag = true;

        if(flag) 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();
            }
        }

        boolean flag = false;
        if(c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2])
            flag = true;

        if(flag) 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 boolean flag = false; flag false if(c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2])
            flag = true; c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2] c[0][0] - c[2][0] == c[0][1] - c[2][1] c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2] c[0][0] - c[1][0] == c[0][1] - c[1][1] c[0][0] - c[1][0] c[0][0] c[0] c 0 0 c[1][0] c[1] c 1 0 c[0][1] - c[1][1] c[0][1] c[0] c 0 1 c[1][1] c[1] c 1 1 c[0][1] - c[1][1] == c[0][2] - c[1][2] c[0][1] - c[1][1] c[0][1] c[0] c 0 1 c[1][1] c[1] c 1 1 c[0][2] - c[1][2] c[0][2] c[0] c 0 2 c[1][2] c[1] c 1 2 c[0][0] - c[2][0] == c[0][1] - c[2][1] c[0][0] - c[2][0] c[0][0] c[0] c 0 0 c[2][0] c[2] c 2 0 c[0][1] - c[2][1] c[0][1] c[0] c 0 1 c[2][1] c[2] c 2 1 c[0][1] - c[2][1] == c[0][2] - c[2][2] c[0][1] - c[2][1] c[0][1] c[0] c 0 1 c[2][1] c[2] c 2 1 c[0][2] - c[2][2] c[0][2] c[0] c 0 2 c[2][2] c[2] c 2 2 flag = true flag true if(flag) System.out.println("Yes");
        else System.out.println("No"); flag 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
import java.util.*;

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 flag = false;
        if(c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][1] - c[1][1] == c[0][2] - c[1][2] &&
           c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][1] - c[2][1] == c[0][2] - c[2][2])
            flag = true;

        if(flag) System.out.println("Yes");
        else System.out.println("No");
          
    }
}