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();
        }
      }
      if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No");
    }
    public static int lcm(int x, int y){
      return x*y/gcd(x,y);
    }
    public static int gcd(int x, int y){
      if(x < y)return gcd(y,x);
      if(y==0)return x;
      return gcd(y,x%y);
    }
} 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();
        }
      }
      if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No");
    }
    public static int lcm(int x, int y){
      return x*y/gcd(x,y);
    }
    public static int gcd(int x, int y){
      if(x < y)return gcd(y,x);
      if(y==0)return x;
      return gcd(y,x%y);
    }
} 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();
        }
      }
      if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No");
    } 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();
        }
      }
      if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No");
    } 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 if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No"); c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0] c[2][1]==c[2][0]+c[0][1]-c[0][0] c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0] c[1][1]==c[0][1]+c[1][0]-c[0][0] c[1][1] c[1] c 1 1 c[0][1]+c[1][0]-c[0][0] c[0][1]+c[1][0] c[0][1] c[0] c 0 1 c[1][0] c[1] c 1 0 c[0][0] c[0] c 0 0 c[1][2]==c[1][0]+c[0][2]-c[0][0] c[1][2] c[1] c 1 2 c[1][0]+c[0][2]-c[0][0] c[1][0]+c[0][2] c[1][0] c[1] c 1 0 c[0][2] c[0] c 0 2 c[0][0] c[0] c 0 0 c[2][1]==c[2][0]+c[0][1]-c[0][0] c[2][1] c[2] c 2 1 c[2][0]+c[0][1]-c[0][0] c[2][0]+c[0][1] c[2][0] c[2] c 2 0 c[0][1] c[0] c 0 1 c[0][0] c[0] c 0 0 c[2][2]==c[2][0]+c[0][2]-c[0][0] c[2][2] c[2] c 2 2 c[2][0]+c[0][2]-c[0][0] c[2][0]+c[0][2] c[2][0] c[2] c 2 0 c[0][2] c[0] c 0 2 c[0][0] c[0] c 0 0 System.out.println("Yes") System.out.println System.out System System.out "Yes" System.out.println("No") System.out.println System.out System System.out "No" String[] args args public static int lcm(int x, int y){
      return x*y/gcd(x,y);
    } lcm {
      return x*y/gcd(x,y);
    } return x*y/gcd(x,y); x*y/gcd(x,y) x*y x y gcd(x,y) gcd x y int x x int y y public static int gcd(int x, int y){
      if(x < y)return gcd(y,x);
      if(y==0)return x;
      return gcd(y,x%y);
    } gcd {
      if(x < y)return gcd(y,x);
      if(y==0)return x;
      return gcd(y,x%y);
    } if(x < y)return gcd(y,x); x < y x y return gcd(y,x); gcd(y,x) gcd y x if(y==0)return x; y==0 y 0 return x; x return gcd(y,x%y); gcd(y,x%y) gcd y x%y x y int x x int y y 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();
        }
      }
      if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No");
    }
    public static int lcm(int x, int y){
      return x*y/gcd(x,y);
    }
    public static int gcd(int x, int y){
      if(x < y)return gcd(y,x);
      if(y==0)return x;
      return gcd(y,x%y);
    }
} 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();
        }
      }
      if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No");
    }
    public static int lcm(int x, int y){
      return x*y/gcd(x,y);
    }
    public static int gcd(int x, int y){
      if(x < y)return gcd(y,x);
      if(y==0)return x;
      return gcd(y,x%y);
    }
} 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();
        }
      }
      if(c[1][1]==c[0][1]+c[1][0]-c[0][0]&&c[1][2]==c[1][0]+c[0][2]-c[0][0]&&c[2][1]==c[2][0]+c[0][1]-c[0][0]&&c[2][2]==c[2][0]+c[0][2]-c[0][0])System.out.println("Yes");
      else System.out.println("No");
    }
    public static int lcm(int x, int y){
      return x*y/gcd(x,y);
    }
    public static int gcd(int x, int y){
      if(x < y)return gcd(y,x);
      if(y==0)return x;
      return gcd(y,x%y);
    }
}