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] = sc.nextInt();
            }
        }

        int[] a = new int[3];
        int[] b = new int[3];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "Yes" : "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] = sc.nextInt();
            }
        }

        int[] a = new int[3];
        int[] b = new int[3];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "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 < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }

        int[] a = new int[3];
        int[] b = new int[3];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "Yes" : "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();
            }
        }

        int[] a = new int[3];
        int[] b = new int[3];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "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 < 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 int[] a = new int[3]; a new int[3] 3 int[] b = new int[3]; b new int[3] 3 a[0] = 0 a[0] a 0 0 for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0]; int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i b[i] = c[0][i] - a[0]; b[i] = c[0][i] - a[0] b[i] b i c[0][i] - a[0] c[0][i] c[0] c 0 i a[0] a 0 for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0]; int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i a[i] = c[i][0] - b[0]; a[i] = c[i][0] - b[0] a[i] a i c[i][0] - b[0] c[i][0] c[i] c i 0 b[0] b 0 boolean good = true; good true for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        } int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        } {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        } for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                if (a[i] + b[j] != c[i][j]) good = false;
            } {
                if (a[i] + b[j] != c[i][j]) good = false;
            } if (a[i] + b[j] != c[i][j]) good = false; a[i] + b[j] != c[i][j] a[i] + b[j] a[i] a i b[j] b j c[i][j] c[i] c i j good = false good false System.out.println(good ? "Yes" : "No") System.out.println System.out System System.out good ? "Yes" : "No" good "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 < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }

        int[] a = new int[3];
        int[] b = new int[3];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "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 < 3; i++) {
            for (int j = 0; j < 3; j++) {
                c[i][j] = sc.nextInt();
            }
        }

        int[] a = new int[3];
        int[] b = new int[3];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "Yes" : "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] = sc.nextInt();
            }
        }

        int[] a = new int[3];
        int[] b = new int[3];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "Yes" : "No");
    }
}
