import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int[][] c = new int[4][4];
        c[1][1]=scanner.nextInt();
        c[1][2]=scanner.nextInt();
        c[1][3]=scanner.nextInt();
        c[2][1]=scanner.nextInt();
        c[2][2]=scanner.nextInt();
        c[2][3]=scanner.nextInt();
        c[3][1]=scanner.nextInt();
        c[3][2]=scanner.nextInt();
        c[3][3]=scanner.nextInt();
        boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3];
        boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3];
        boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1];
        boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2];
        if (b1&&b2&&b3&&b4){
            System.out.println("Yes");
        }else {
            System.out.println("No");
        }

    }

} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int[][] c = new int[4][4];
        c[1][1]=scanner.nextInt();
        c[1][2]=scanner.nextInt();
        c[1][3]=scanner.nextInt();
        c[2][1]=scanner.nextInt();
        c[2][2]=scanner.nextInt();
        c[2][3]=scanner.nextInt();
        c[3][1]=scanner.nextInt();
        c[3][2]=scanner.nextInt();
        c[3][3]=scanner.nextInt();
        boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3];
        boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3];
        boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1];
        boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2];
        if (b1&&b2&&b3&&b4){
            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[4][4];
        c[1][1]=scanner.nextInt();
        c[1][2]=scanner.nextInt();
        c[1][3]=scanner.nextInt();
        c[2][1]=scanner.nextInt();
        c[2][2]=scanner.nextInt();
        c[2][3]=scanner.nextInt();
        c[3][1]=scanner.nextInt();
        c[3][2]=scanner.nextInt();
        c[3][3]=scanner.nextInt();
        boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3];
        boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3];
        boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1];
        boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2];
        if (b1&&b2&&b3&&b4){
            System.out.println("Yes");
        }else {
            System.out.println("No");
        }

    } main {
        Scanner scanner = new Scanner(System.in);
        int[][] c = new int[4][4];
        c[1][1]=scanner.nextInt();
        c[1][2]=scanner.nextInt();
        c[1][3]=scanner.nextInt();
        c[2][1]=scanner.nextInt();
        c[2][2]=scanner.nextInt();
        c[2][3]=scanner.nextInt();
        c[3][1]=scanner.nextInt();
        c[3][2]=scanner.nextInt();
        c[3][3]=scanner.nextInt();
        boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3];
        boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3];
        boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1];
        boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2];
        if (b1&&b2&&b3&&b4){
            System.out.println("Yes");
        }else {
            System.out.println("No");
        }

    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int[][] c = new int[4][4]; c new int[4][4] 4 4 c[1][1]=scanner.nextInt() c[1][1] c[1] c 1 1 scanner.nextInt() scanner.nextInt scanner c[1][2]=scanner.nextInt() c[1][2] c[1] c 1 2 scanner.nextInt() scanner.nextInt scanner c[1][3]=scanner.nextInt() c[1][3] c[1] c 1 3 scanner.nextInt() scanner.nextInt scanner c[2][1]=scanner.nextInt() c[2][1] c[2] c 2 1 scanner.nextInt() scanner.nextInt scanner c[2][2]=scanner.nextInt() c[2][2] c[2] c 2 2 scanner.nextInt() scanner.nextInt scanner c[2][3]=scanner.nextInt() c[2][3] c[2] c 2 3 scanner.nextInt() scanner.nextInt scanner c[3][1]=scanner.nextInt() c[3][1] c[3] c 3 1 scanner.nextInt() scanner.nextInt scanner c[3][2]=scanner.nextInt() c[3][2] c[3] c 3 2 scanner.nextInt() scanner.nextInt scanner c[3][3]=scanner.nextInt() c[3][3] c[3] c 3 3 scanner.nextInt() scanner.nextInt scanner boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3]; b1 c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3] c[2][1]-c[1][1]==c[2][2]-c[1][2] c[2][1]-c[1][1] c[2][1] c[2] c 2 1 c[1][1] c[1] c 1 1 c[2][2]-c[1][2] c[2][2] c[2] c 2 2 c[1][2] c[1] c 1 2 c[2][2]-c[1][2]==c[2][3]-c[1][3] c[2][2]-c[1][2] c[2][2] c[2] c 2 2 c[1][2] c[1] c 1 2 c[2][3]-c[1][3] c[2][3] c[2] c 2 3 c[1][3] c[1] c 1 3 boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3]; b2 c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3] c[3][1]-c[2][1]==c[3][2]-c[2][2] c[3][1]-c[2][1] c[3][1] c[3] c 3 1 c[2][1] c[2] c 2 1 c[3][2]-c[2][2] c[3][2] c[3] c 3 2 c[2][2] c[2] c 2 2 c[3][2]-c[2][2]==c[3][3]-c[2][3] c[3][2]-c[2][2] c[3][2] c[3] c 3 2 c[2][2] c[2] c 2 2 c[3][3]-c[2][3] c[3][3] c[3] c 3 3 c[2][3] c[2] c 2 3 boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1]; b3 c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1] c[1][2]-c[1][1]==c[2][2]-c[2][1] c[1][2]-c[1][1] c[1][2] c[1] c 1 2 c[1][1] c[1] c 1 1 c[2][2]-c[2][1] c[2][2] c[2] c 2 2 c[2][1] c[2] c 2 1 c[2][2]-c[2][1]==c[3][2]-c[3][1] c[2][2]-c[2][1] c[2][2] c[2] c 2 2 c[2][1] c[2] c 2 1 c[3][2]-c[3][1] c[3][2] c[3] c 3 2 c[3][1] c[3] c 3 1 boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2]; b4 c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2] c[1][3]-c[1][2]==c[2][3]-c[2][2] c[1][3]-c[1][2] c[1][3] c[1] c 1 3 c[1][2] c[1] c 1 2 c[2][3]-c[2][2] c[2][3] c[2] c 2 3 c[2][2] c[2] c 2 2 c[2][3]-c[2][2]==c[3][3]-c[3][2] c[2][3]-c[2][2] c[2][3] c[2] c 2 3 c[2][2] c[2] c 2 2 c[3][3]-c[3][2] c[3][3] c[3] c 3 3 c[3][2] c[3] c 3 2 if (b1&&b2&&b3&&b4){
            System.out.println("Yes");
        }else {
            System.out.println("No");
        } b1&&b2&&b3&&b4 b3 b1&&b2&&b3&&b4 b1 b2 b3 b4 {
            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[4][4];
        c[1][1]=scanner.nextInt();
        c[1][2]=scanner.nextInt();
        c[1][3]=scanner.nextInt();
        c[2][1]=scanner.nextInt();
        c[2][2]=scanner.nextInt();
        c[2][3]=scanner.nextInt();
        c[3][1]=scanner.nextInt();
        c[3][2]=scanner.nextInt();
        c[3][3]=scanner.nextInt();
        boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3];
        boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3];
        boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1];
        boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2];
        if (b1&&b2&&b3&&b4){
            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[4][4];
        c[1][1]=scanner.nextInt();
        c[1][2]=scanner.nextInt();
        c[1][3]=scanner.nextInt();
        c[2][1]=scanner.nextInt();
        c[2][2]=scanner.nextInt();
        c[2][3]=scanner.nextInt();
        c[3][1]=scanner.nextInt();
        c[3][2]=scanner.nextInt();
        c[3][3]=scanner.nextInt();
        boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3];
        boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3];
        boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1];
        boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2];
        if (b1&&b2&&b3&&b4){
            System.out.println("Yes");
        }else {
            System.out.println("No");
        }

    }

} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int[][] c = new int[4][4];
        c[1][1]=scanner.nextInt();
        c[1][2]=scanner.nextInt();
        c[1][3]=scanner.nextInt();
        c[2][1]=scanner.nextInt();
        c[2][2]=scanner.nextInt();
        c[2][3]=scanner.nextInt();
        c[3][1]=scanner.nextInt();
        c[3][2]=scanner.nextInt();
        c[3][3]=scanner.nextInt();
        boolean b1 = c[2][1]-c[1][1]==c[2][2]-c[1][2]&&c[2][2]-c[1][2]==c[2][3]-c[1][3];
        boolean b2 = c[3][1]-c[2][1]==c[3][2]-c[2][2]&&c[3][2]-c[2][2]==c[3][3]-c[2][3];
        boolean b3 = c[1][2]-c[1][1]==c[2][2]-c[2][1]&&c[2][2]-c[2][1]==c[3][2]-c[3][1];
        boolean b4 = c[1][3]-c[1][2]==c[2][3]-c[2][2]&&c[2][3]-c[2][2]==c[3][3]-c[3][2];
        if (b1&&b2&&b3&&b4){
            System.out.println("Yes");
        }else {
            System.out.println("No");
        }

    }

}