import java.util.*;

public class Main {

  public static void main (String[] args) {

    int[][] c = new int[3][3];

    Scanner sc = new Scanner(System.in);
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        c[i][j] = sc.nextInt();
      }
    }
    sc.close();

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

    a[0] = 0;
    b[0] = c[0][0];
    b[1] = c[0][1];
    b[2] = c[0][2];
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    String answer = "Yes";

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    }

    System.out.println(answer);

  }

} import java.util.*; util.* java public class Main {

  public static void main (String[] args) {

    int[][] c = new int[3][3];

    Scanner sc = new Scanner(System.in);
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        c[i][j] = sc.nextInt();
      }
    }
    sc.close();

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

    a[0] = 0;
    b[0] = c[0][0];
    b[1] = c[0][1];
    b[2] = c[0][2];
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    String answer = "Yes";

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    }

    System.out.println(answer);

  }

} Main public static void main (String[] args) {

    int[][] c = new int[3][3];

    Scanner sc = new Scanner(System.in);
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        c[i][j] = sc.nextInt();
      }
    }
    sc.close();

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

    a[0] = 0;
    b[0] = c[0][0];
    b[1] = c[0][1];
    b[2] = c[0][2];
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    String answer = "Yes";

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    }

    System.out.println(answer);

  } main {

    int[][] c = new int[3][3];

    Scanner sc = new Scanner(System.in);
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        c[i][j] = sc.nextInt();
      }
    }
    sc.close();

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

    a[0] = 0;
    b[0] = c[0][0];
    b[1] = c[0][1];
    b[2] = c[0][2];
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    String answer = "Yes";

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    }

    System.out.println(answer);

  } int[][] c = new int[3][3]; c new int[3][3] 3 3 Scanner sc = new Scanner(System.in); sc new Scanner(System.in) 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 sc.close() sc.close 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] b[0] b 0 c[0][0] c[0] c 0 0 b[1] = c[0][1] b[1] b 1 c[0][1] c[0] c 0 1 b[2] = c[0][2] b[2] b 2 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 String answer = "Yes"; answer "Yes" for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    } 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]) {
          answer = "No";
        }
      }
    } {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    } for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      } {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      } if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        } 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 {
          answer = "No";
        } answer = "No" answer "No" System.out.println(answer) System.out.println System.out System System.out answer String[] args args public class Main {

  public static void main (String[] args) {

    int[][] c = new int[3][3];

    Scanner sc = new Scanner(System.in);
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        c[i][j] = sc.nextInt();
      }
    }
    sc.close();

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

    a[0] = 0;
    b[0] = c[0][0];
    b[1] = c[0][1];
    b[2] = c[0][2];
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    String answer = "Yes";

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    }

    System.out.println(answer);

  }

} public class Main {

  public static void main (String[] args) {

    int[][] c = new int[3][3];

    Scanner sc = new Scanner(System.in);
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        c[i][j] = sc.nextInt();
      }
    }
    sc.close();

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

    a[0] = 0;
    b[0] = c[0][0];
    b[1] = c[0][1];
    b[2] = c[0][2];
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    String answer = "Yes";

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    }

    System.out.println(answer);

  }

} Main
import java.util.*;

public class Main {

  public static void main (String[] args) {

    int[][] c = new int[3][3];

    Scanner sc = new Scanner(System.in);
    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        c[i][j] = sc.nextInt();
      }
    }
    sc.close();

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

    a[0] = 0;
    b[0] = c[0][0];
    b[1] = c[0][1];
    b[2] = c[0][2];
    a[1] = c[1][0] - b[0];
    a[2] = c[2][0] - b[0];

    String answer = "Yes";

    for (int i = 0; i < 3; i++) {
      for (int j = 0; j < 3; j++) {
        if (c[i][j] != a[i] + b[j]) {
          answer = "No";
        }
      }
    }

    System.out.println(answer);

  }

}