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 < 9; i++) c[i/3][i%3] = sc.nextInt();
        System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "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 < 9; i++) c[i/3][i%3] = sc.nextInt();
        System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "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 < 9; i++) c[i/3][i%3] = sc.nextInt();
        System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "No");
    } main {
        Scanner sc = new Scanner(System.in);
        int[][] c = new int[3][3];
        for (int i = 0; i < 9; i++) c[i/3][i%3] = sc.nextInt();
        System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "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 < 9; i++) c[i/3][i%3] = sc.nextInt(); int i = 0; int i = 0; i 0 i < 9 i 9 i++ i++ i c[i/3][i%3] = sc.nextInt(); c[i/3][i%3] = sc.nextInt() c[i/3][i%3] c[i/3] c i/3 i 3 i%3 i 3 sc.nextInt() sc.nextInt sc System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "No") System.out.println System.out System System.out c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "No" c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2] c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2] c[0][0]+c[1][1]==c[0][1]+c[1][0] c[0][0]+c[1][1] c[0][0] c[0] c 0 0 c[1][1] c[1] c 1 1 c[0][1]+c[1][0] c[0][1] c[0] c 0 1 c[1][0] c[1] c 1 0 c[0][2]+c[2][0]==c[0][0]+c[2][2] c[0][2]+c[2][0] c[0][2] c[0] c 0 2 c[2][0] c[2] c 2 0 c[0][0]+c[2][2] c[0][0] c[0] c 0 0 c[2][2] c[2] c 2 2 c[1][2]+c[2][1]==c[1][1]+c[2][2] c[1][2]+c[2][1] c[1][2] c[1] c 1 2 c[2][1] c[2] c 2 1 c[1][1]+c[2][2] c[1][1] c[1] c 1 1 c[2][2] c[2] c 2 2 "Yes" "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 < 9; i++) c[i/3][i%3] = sc.nextInt();
        System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "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 < 9; i++) c[i/3][i%3] = sc.nextInt();
        System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "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 < 9; i++) c[i/3][i%3] = sc.nextInt();
        System.out.println(c[0][0]+c[1][1]==c[0][1]+c[1][0] && c[0][2]+c[2][0]==c[0][0]+c[2][2] && c[1][2]+c[2][1]==c[1][1]+c[2][2]? "Yes": "No");
    }
}