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];
    a[0] = 0;
    int[] b = { c[0][0], c[0][1], c[0][2] };
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  }
} 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];
    a[0] = 0;
    int[] b = { c[0][0], c[0][1], c[0][2] };
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  }
} 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];
    a[0] = 0;
    int[] b = { c[0][0], c[0][1], c[0][2] };
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  } 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];
    a[0] = 0;
    int[] b = { c[0][0], c[0][1], c[0][2] };
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  } 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 a[0] = 0 a[0] a 0 0 int[] b = { c[0][0], c[0][1], c[0][2] }; b { c[0][0], c[0][1], c[0][2] } c[0][0] c[0] c 0 0 c[0][1] c[0] c 0 1 c[0][2] c[0] c 0 2 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 for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    } 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]) {
          System.out.println("No");
          return;
        }
      }
    } {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    } for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      } {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      } if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        } (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 {
          System.out.println("No");
          return;
        } System.out.println("No") System.out.println System.out System System.out "No" return; System.out.println("Yes") System.out.println System.out System System.out "Yes" 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];
    a[0] = 0;
    int[] b = { c[0][0], c[0][1], c[0][2] };
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  }
} 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];
    a[0] = 0;
    int[] b = { c[0][0], c[0][1], c[0][2] };
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  }
} 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];
    a[0] = 0;
    int[] b = { c[0][0], c[0][1], c[0][2] };
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if ((a[i] + b[j]) != c[i][j]) {
          System.out.println("No");
          return;
        }
      }
    }

    System.out.println("Yes");

  }
}