import java.util.*;
public class Main {

  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      int[][] grid = new int[3][3];
      for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      }
      for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      }
      System.out.println("Yes");
  }
} import java.util.*; util.* java public class Main {

  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      int[][] grid = new int[3][3];
      for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      }
      for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      }
      System.out.println("Yes");
  }
} Main public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      int[][] grid = new int[3][3];
      for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      }
      for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      }
      System.out.println("Yes");
  } main { 
      Scanner sc = new Scanner(System.in);
      int[][] grid = new int[3][3];
      for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      }
      for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      }
      System.out.println("Yes");
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[][] grid = new int[3][3]; grid new int[3][3] 3 3 for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[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++)
          grid[i][j] = sc.nextInt();
      } {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      } for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt(); int j = 0; int j = 0; j 0 j < 3 j 3 j++ j++ j grid[i][j] = sc.nextInt(); grid[i][j] = sc.nextInt() grid[i][j] grid[i] grid i j sc.nextInt() sc.nextInt sc for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      } int i = 0; int i = 0; i 0 i < 2 i 2 i++ i++ i {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      } {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      } for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        } int j = 0; int j = 0; j 0 j < 2 j 2 j++ j++ j {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        } {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        } if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          } grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j] grid[i][j] + grid[i+1][j+1] grid[i][j] grid[i] grid i j grid[i+1][j+1] grid[i+1] grid i+1 i 1 j+1 j 1 grid[i][j+1] + grid[i+1][j] grid[i][j+1] grid[i] grid i j+1 j 1 grid[i+1][j] grid[i+1] grid i+1 i 1 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[][] grid = new int[3][3];
      for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      }
      for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][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[][] grid = new int[3][3];
      for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      }
      for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      }
      System.out.println("Yes");
  }
} Main
import java.util.*;
public class Main {

  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      int[][] grid = new int[3][3];
      for(int i = 0; i < 3; i++) {
        for(int j = 0; j < 3; j++)
          grid[i][j] = sc.nextInt();
      }
      for(int i = 0; i < 2; i++) {
        for(int j = 0; j < 2; j++) {
          if(grid[i][j] + grid[i+1][j+1] != grid[i][j+1] + grid[i+1][j]) {
            System.out.println("No");
            return;
          }
        }
      }
      System.out.println("Yes");
  }
}