import java.util.*;

public class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    c[0][0] = Integer.parseInt(sc.next());
    c[0][1] = Integer.parseInt(sc.next());
    c[0][2] = Integer.parseInt(sc.next());
    c[1][0] = Integer.parseInt(sc.next());
    c[1][1] = Integer.parseInt(sc.next());
    c[1][2] = Integer.parseInt(sc.next());
    c[2][0] = Integer.parseInt(sc.next());
    c[2][1] = Integer.parseInt(sc.next());
    c[2][2] = Integer.parseInt(sc.next());
    
    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][1] - b[1];
    a[2] = c[2][1] - b[1];
    
    String ans = "Yes";
    for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    }
    System.out.println(ans);
  }
} import java.util.*; util.* java public class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    c[0][0] = Integer.parseInt(sc.next());
    c[0][1] = Integer.parseInt(sc.next());
    c[0][2] = Integer.parseInt(sc.next());
    c[1][0] = Integer.parseInt(sc.next());
    c[1][1] = Integer.parseInt(sc.next());
    c[1][2] = Integer.parseInt(sc.next());
    c[2][0] = Integer.parseInt(sc.next());
    c[2][1] = Integer.parseInt(sc.next());
    c[2][2] = Integer.parseInt(sc.next());
    
    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][1] - b[1];
    a[2] = c[2][1] - b[1];
    
    String ans = "Yes";
    for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    }
    System.out.println(ans);
  }
} Main public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    c[0][0] = Integer.parseInt(sc.next());
    c[0][1] = Integer.parseInt(sc.next());
    c[0][2] = Integer.parseInt(sc.next());
    c[1][0] = Integer.parseInt(sc.next());
    c[1][1] = Integer.parseInt(sc.next());
    c[1][2] = Integer.parseInt(sc.next());
    c[2][0] = Integer.parseInt(sc.next());
    c[2][1] = Integer.parseInt(sc.next());
    c[2][2] = Integer.parseInt(sc.next());
    
    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][1] - b[1];
    a[2] = c[2][1] - b[1];
    
    String ans = "Yes";
    for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    }
    System.out.println(ans);
  } main {
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    c[0][0] = Integer.parseInt(sc.next());
    c[0][1] = Integer.parseInt(sc.next());
    c[0][2] = Integer.parseInt(sc.next());
    c[1][0] = Integer.parseInt(sc.next());
    c[1][1] = Integer.parseInt(sc.next());
    c[1][2] = Integer.parseInt(sc.next());
    c[2][0] = Integer.parseInt(sc.next());
    c[2][1] = Integer.parseInt(sc.next());
    c[2][2] = Integer.parseInt(sc.next());
    
    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][1] - b[1];
    a[2] = c[2][1] - b[1];
    
    String ans = "Yes";
    for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    }
    System.out.println(ans);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[][] c = new int[3][3]; c new int[3][3] 3 3 c[0][0] = Integer.parseInt(sc.next()) c[0][0] c[0] c 0 0 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[0][1] = Integer.parseInt(sc.next()) c[0][1] c[0] c 0 1 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[0][2] = Integer.parseInt(sc.next()) c[0][2] c[0] c 0 2 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[1][0] = Integer.parseInt(sc.next()) c[1][0] c[1] c 1 0 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[1][1] = Integer.parseInt(sc.next()) c[1][1] c[1] c 1 1 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[1][2] = Integer.parseInt(sc.next()) c[1][2] c[1] c 1 2 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[2][0] = Integer.parseInt(sc.next()) c[2][0] c[2] c 2 0 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[2][1] = Integer.parseInt(sc.next()) c[2][1] c[2] c 2 1 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc c[2][2] = Integer.parseInt(sc.next()) c[2][2] c[2] c 2 2 Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next 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][1] - b[1] a[1] a 1 c[1][1] - b[1] c[1][1] c[1] c 1 1 b[1] b 1 a[2] = c[2][1] - b[1] a[2] a 2 c[2][1] - b[1] c[2][1] c[2] c 2 1 b[1] b 1 String ans = "Yes"; ans "Yes" for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    } 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]){
          ans = "No";
          break;
        }
      }
    } {
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    } for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      } int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j {
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      } {
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      } if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        } 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 {
          ans = "No";
          break;
        } ans = "No" ans "No" break; System.out.println(ans) System.out.println System.out System System.out ans String[]args args public class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    c[0][0] = Integer.parseInt(sc.next());
    c[0][1] = Integer.parseInt(sc.next());
    c[0][2] = Integer.parseInt(sc.next());
    c[1][0] = Integer.parseInt(sc.next());
    c[1][1] = Integer.parseInt(sc.next());
    c[1][2] = Integer.parseInt(sc.next());
    c[2][0] = Integer.parseInt(sc.next());
    c[2][1] = Integer.parseInt(sc.next());
    c[2][2] = Integer.parseInt(sc.next());
    
    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][1] - b[1];
    a[2] = c[2][1] - b[1];
    
    String ans = "Yes";
    for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    }
    System.out.println(ans);
  }
} public class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    c[0][0] = Integer.parseInt(sc.next());
    c[0][1] = Integer.parseInt(sc.next());
    c[0][2] = Integer.parseInt(sc.next());
    c[1][0] = Integer.parseInt(sc.next());
    c[1][1] = Integer.parseInt(sc.next());
    c[1][2] = Integer.parseInt(sc.next());
    c[2][0] = Integer.parseInt(sc.next());
    c[2][1] = Integer.parseInt(sc.next());
    c[2][2] = Integer.parseInt(sc.next());
    
    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][1] - b[1];
    a[2] = c[2][1] - b[1];
    
    String ans = "Yes";
    for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    }
    System.out.println(ans);
  }
} Main
import java.util.*;

public class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    int[][] c = new int[3][3];
    c[0][0] = Integer.parseInt(sc.next());
    c[0][1] = Integer.parseInt(sc.next());
    c[0][2] = Integer.parseInt(sc.next());
    c[1][0] = Integer.parseInt(sc.next());
    c[1][1] = Integer.parseInt(sc.next());
    c[1][2] = Integer.parseInt(sc.next());
    c[2][0] = Integer.parseInt(sc.next());
    c[2][1] = Integer.parseInt(sc.next());
    c[2][2] = Integer.parseInt(sc.next());
    
    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][1] - b[1];
    a[2] = c[2][1] - b[1];
    
    String ans = "Yes";
    for(int i = 0; i < 3; i++){
      for(int j = 0; j < 3; j++){
        if(c[i][j] != a[i] + b[j]){
          ans = "No";
          break;
        }
      }
    }
    System.out.println(ans);
  }
}