import java.util.*;

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;
        b[0] = c[0][0] - a[0];
        b[1] = c[0][1] - a[0];
        b[2] = c[0][2] - a[0];
        a[1] = c[1][0] - b[0];
        a[2] = c[2][0] - b[0];
        boolean isYes = true;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        }
        System.out.println(isYes ? "Yes" : "No");
    }
} import java.util.*; util.* java 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;
        b[0] = c[0][0] - a[0];
        b[1] = c[0][1] - a[0];
        b[2] = c[0][2] - a[0];
        a[1] = c[1][0] - b[0];
        a[2] = c[2][0] - b[0];
        boolean isYes = true;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        }
        System.out.println(isYes ? "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;
        b[0] = c[0][0] - a[0];
        b[1] = c[0][1] - a[0];
        b[2] = c[0][2] - a[0];
        a[1] = c[1][0] - b[0];
        a[2] = c[2][0] - b[0];
        boolean isYes = true;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        }
        System.out.println(isYes ? "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;
        b[0] = c[0][0] - a[0];
        b[1] = c[0][1] - a[0];
        b[2] = c[0][2] - a[0];
        a[1] = c[1][0] - b[0];
        a[2] = c[2][0] - b[0];
        boolean isYes = true;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        }
        System.out.println(isYes ? "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 b[0] = c[0][0] - a[0] b[0] b 0 c[0][0] - a[0] c[0][0] c[0] c 0 0 a[0] a 0 b[1] = c[0][1] - a[0] b[1] b 1 c[0][1] - a[0] c[0][1] c[0] c 0 1 a[0] a 0 b[2] = c[0][2] - a[0] b[2] b 2 c[0][2] - a[0] c[0][2] c[0] c 0 2 a[0] a 0 a[1] = c[1][0] - b[0] a[1] a 1 c[1][0] - b[0] c[1][0] c[1] c 1 0 b[0] b 0 a[2] = c[2][0] - b[0] a[2] a 2 c[2][0] - b[0] c[2][0] c[2] c 2 0 b[0] b 0 boolean isYes = true; isYes true for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        } int i = 0; int i = 0; i 0 i < 3 i 3 i++ i++ i {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        } {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        } for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            } {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            } if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                } c[i][j] != a[i] + b[j] c[i][j] c[i] c i j a[i] + b[j] a[i] a i b[j] b j {
                    isYes = false;
                } isYes = false isYes false System.out.println(isYes ? "Yes" : "No") System.out.println System.out System System.out isYes ? "Yes" : "No" isYes "Yes" "No" String args[] args
import java.util.*;

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;
        b[0] = c[0][0] - a[0];
        b[1] = c[0][1] - a[0];
        b[2] = c[0][2] - a[0];
        a[1] = c[1][0] - b[0];
        a[2] = c[2][0] - b[0];
        boolean isYes = true;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        }
        System.out.println(isYes ? "Yes" : "No");
    }
}