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