import 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();
        }
      }
      String ans = "Yes";
      for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      }
      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];
      for(int i = 0; i < 3; i++){
        for(int j = 0; j < 3; j++){
          c[i][j] = sc.nextInt();
        }
      }
      String ans = "Yes";
      for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      }
      System.out.println(ans);
    }
} 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();
        }
      }
      String ans = "Yes";
      for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      }
      System.out.println(ans);
    } 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();
        }
      }
      String ans = "Yes";
      for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      }
      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 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 String ans = "Yes"; ans "Yes" for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      } int i = 0; int i = 0; i 0 i < 2 i 2 i++ i++ i {
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      } {
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      } if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        } !(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1]) (c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1]) c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] c[0][i]-c[0][i+1] c[0][i] c[0] c 0 i c[0][i+1] c[0] c 0 i+1 i 1 c[1][i]-c[1][i+1] c[1][i] c[1] c 1 i c[1][i+1] c[1] c 1 i+1 i 1 c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1] c[0][i]-c[0][i+1] c[0][i] c[0] c 0 i c[0][i+1] c[0] c 0 i+1 i 1 c[2][i]-c[2][i+1] c[2][i] c[2] c 2 i c[2][i+1] c[2] c 2 i+1 i 1 {
           ans = "No";
        } ans = "No" ans "No" 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];
      for(int i = 0; i < 3; i++){
        for(int j = 0; j < 3; j++){
          c[i][j] = sc.nextInt();
        }
      }
      String ans = "Yes";
      for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      }
      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];
      for(int i = 0; i < 3; i++){
        for(int j = 0; j < 3; j++){
          c[i][j] = sc.nextInt();
        }
      }
      String ans = "Yes";
      for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      }
      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];
      for(int i = 0; i < 3; i++){
        for(int j = 0; j < 3; j++){
          c[i][j] = sc.nextInt();
        }
      }
      String ans = "Yes";
      for(int i = 0; i < 2; i++){
        if(!(c[0][i]-c[0][i+1]==c[1][i]-c[1][i+1] && c[0][i]-c[0][i+1]==c[2][i]-c[2][i+1])){
           ans = "No";
        }
      }
      System.out.println(ans);
    }
}