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] = Integer.parseInt(sc.next());
            }
        }
        for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        }
        System.out.println("No");
    }
} 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] = Integer.parseInt(sc.next());
            }
        }
        for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        }
        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] = Integer.parseInt(sc.next());
            }
        }
        for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        }
        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] = Integer.parseInt(sc.next());
            }
        }
        for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        }
        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] = Integer.parseInt(sc.next());
            }
        } 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] = Integer.parseInt(sc.next());
            }
        } {
            for (int j = 0; j < 3; j++) {
                c[i][j] = Integer.parseInt(sc.next());
            }
        } for (int j = 0; j < 3; j++) {
                c[i][j] = Integer.parseInt(sc.next());
            } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                c[i][j] = Integer.parseInt(sc.next());
            } {
                c[i][j] = Integer.parseInt(sc.next());
            } c[i][j] = Integer.parseInt(sc.next()) c[i][j] c[i] c i j Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        } int i = 0; int i = 0; i 0 i <= c[0][0] i c[0][0] c[0] c 0 0 i++ i++ i {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        } {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        } int b1 = c[0][0] - i; b1 c[0][0] - i c[0][0] c[0] c 0 0 i int b2 = c[0][1] - i; b2 c[0][1] - i c[0][1] c[0] c 0 1 i int b3 = c[0][2] - i; b3 c[0][2] - i c[0][2] c[0] c 0 2 i if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            } c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3 c[1][0] - b1 != c[1][1] - b2 c[1][0] - b1 c[1][0] c[1] c 1 0 b1 c[1][1] - b2 c[1][1] c[1] c 1 1 b2 c[1][1] - b2 != c[1][2] - b3 c[1][1] - b2 c[1][1] c[1] c 1 1 b2 c[1][2] - b3 c[1][2] c[1] c 1 2 b3 {
                continue;
            } continue; if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            } c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3 c[2][0] - b1 != c[2][1] - b2 c[2][0] - b1 c[2][0] c[2] c 2 0 b1 c[2][1] - b2 c[2][1] c[2] c 2 1 b2 c[2][1] - b2 != c[2][2] - b3 c[2][1] - b2 c[2][1] c[2] c 2 1 b2 c[2][2] - b3 c[2][2] c[2] c 2 2 b3 {
                continue;
            } continue; System.out.println("Yes") System.out.println System.out System System.out "Yes" return; 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] = Integer.parseInt(sc.next());
            }
        }
        for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        }
        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] = Integer.parseInt(sc.next());
            }
        }
        for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        }
        System.out.println("No");
    }
} 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] = Integer.parseInt(sc.next());
            }
        }
        for (int i = 0; i <= c[0][0]; i++) {
            int b1 = c[0][0] - i;
            int b2 = c[0][1] - i;
            int b3 = c[0][2] - i;
            if (c[1][0] - b1 != c[1][1] - b2 || c[1][1] - b2 != c[1][2] - b3) {
                continue;
            }
            if (c[2][0] - b1 != c[2][1] - b2 || c[2][1] - b2 != c[2][2] - b3) {
                continue;
            }
            System.out.println("Yes");
            return;
        }
        System.out.println("No");
    }
}