import java.util.Scanner;
import java.util.Arrays;

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 ans = true;
        for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        }
        if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        }
        if (ans == true) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} import java.util.Scanner; Scanner java.util import java.util.Arrays; Arrays 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 ans = true;
        for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        }
        if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        }
        if (ans == true) {
            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 ans = true;
        for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        }
        if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        }
        if (ans == true) {
            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 ans = true;
        for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        }
        if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        }
        if (ans == true) {
            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 ans = true; ans true for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        } int i = 0; int i = 0; i 0 i < 2 i 2 i++ i++ i {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        } {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        } if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            } c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1] c[0][i] - c[0][i + 1] c[0][i] c[0] c 0 i c[0][i + 1] c[0] c 0 i + 1 i 1 c[1][i] - c[1][i + 1] c[1][i] c[1] c 1 i c[1][i + 1] c[1] c 1 i + 1 i 1 {
                ans = false;
                break;
            } ans = false ans false break; if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            } c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1] c[1][i] - c[1][i + 1] c[1][i] c[1] c 1 i c[1][i + 1] c[1] c 1 i + 1 i 1 c[2][i] - c[2][i + 1] c[2][i] c[2] c 2 i c[2][i + 1] c[2] c 2 i + 1 i 1 {
                ans = false;
                break;
            } ans = false ans false break; if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        } ans == true ans true {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        } for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            } int i = 0; int i = 0; i 0 i < 2 i 2 i++ i++ i {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            } {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            } if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                } c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1] c[i][0] - c[i + 1][0] c[i][0] c[i] c i 0 c[i + 1][0] c[i + 1] c i + 1 i 1 0 c[i][1] - c[i + 1][1] c[i][1] c[i] c i 1 c[i + 1][1] c[i + 1] c i + 1 i 1 1 {
                    ans = false;
                    break;
                } ans = false ans false break; if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                } c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2] c[i][1] - c[i + 1][1] c[i][1] c[i] c i 1 c[i + 1][1] c[i + 1] c i + 1 i 1 1 c[i][2] - c[i + 1][2] c[i][2] c[i] c i 2 c[i + 1][2] c[i + 1] c i + 1 i 1 2 {
                    ans = false;
                    break;
                } ans = false ans false break; if (ans == true) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } ans == true ans true {
            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 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 ans = true;
        for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        }
        if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        }
        if (ans == true) {
            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();
            }
        }
        boolean ans = true;
        for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        }
        if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        }
        if (ans == true) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
} Main
import java.util.Scanner;
import java.util.Arrays;

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 ans = true;
        for (int i = 0; i < 2; i++) {
            if (c[0][i] - c[0][i + 1] != c[1][i] - c[1][i + 1]) {
                ans = false;
                break;
            }
            if (c[1][i] - c[1][i + 1] != c[2][i] - c[2][i + 1]) {
                ans = false;
                break;
            }
        }
        if (ans == true) {
            for (int i = 0; i < 2; i++) {
                if (c[i][0] - c[i + 1][0] != c[i][1] - c[i + 1][1]) {
                    ans = false;
                    break;
                }
                if (c[i][1] - c[i + 1][1] != c[i][2] - c[i + 1][2]) {
                    ans = false;
                    break;
                }
            }
        }
        if (ans == true) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }
    }
}
