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();
    	    }
    	}
    	
    	int a1 =0;
    	
    	int b1 = c[0][0] - a1;
    	int b2 = c[0][1] - a1;
    	int b3 = c[0][2] - a1;
    	int a2 = c[1][0] - b1;
    	int a3 = c[2][0] - b1;
    	
    	if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    System.out.println("Yes");
    	}
    	
    	else{
    	    System.out.println("No");
    	}
    }
} 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();
    	    }
    	}
    	
    	int a1 =0;
    	
    	int b1 = c[0][0] - a1;
    	int b2 = c[0][1] - a1;
    	int b3 = c[0][2] - a1;
    	int a2 = c[1][0] - b1;
    	int a3 = c[2][0] - b1;
    	
    	if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    System.out.println("Yes");
    	}
    	
    	else{
    	    System.out.println("No");
    	}
    }
} 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();
    	    }
    	}
    	
    	int a1 =0;
    	
    	int b1 = c[0][0] - a1;
    	int b2 = c[0][1] - a1;
    	int b3 = c[0][2] - a1;
    	int a2 = c[1][0] - b1;
    	int a3 = c[2][0] - b1;
    	
    	if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    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();
    	    }
    	}
    	
    	int a1 =0;
    	
    	int b1 = c[0][0] - a1;
    	int b2 = c[0][1] - a1;
    	int b3 = c[0][2] - a1;
    	int a2 = c[1][0] - b1;
    	int a3 = c[2][0] - b1;
    	
    	if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    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 int a1 =0; a1 0 int b1 = c[0][0] - a1; b1 c[0][0] - a1 c[0][0] c[0] c 0 0 a1 int b2 = c[0][1] - a1; b2 c[0][1] - a1 c[0][1] c[0] c 0 1 a1 int b3 = c[0][2] - a1; b3 c[0][2] - a1 c[0][2] c[0] c 0 2 a1 int a2 = c[1][0] - b1; a2 c[1][0] - b1 c[1][0] c[1] c 1 0 b1 int a3 = c[2][0] - b1; a3 c[2][0] - b1 c[2][0] c[2] c 2 0 b1 if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    System.out.println("Yes");
    	}
    	
    	else{
    	    System.out.println("No");
    	} a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2] a3 + b2 == c[2][1] a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2] a2+b2 == c[1][1] a2+b2 a2 b2 c[1][1] c[1] c 1 1 a2 + b3 == c[1][2] a2 + b3 a2 b3 c[1][2] c[1] c 1 2 a3 + b2 == c[2][1] a3 + b2 a3 b2 c[2][1] c[2] c 2 1 a3 + b3 ==c[2][2] a3 + b3 a3 b3 c[2][2] c[2] c 2 2 {
    	    System.out.println("Yes");
    	} System.out.println("Yes") System.out.println System.out System System.out "Yes" {
    	    System.out.println("No");
    	} System.out.println("No") System.out.println System.out System System.out "No" 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();
    	    }
    	}
    	
    	int a1 =0;
    	
    	int b1 = c[0][0] - a1;
    	int b2 = c[0][1] - a1;
    	int b3 = c[0][2] - a1;
    	int a2 = c[1][0] - b1;
    	int a3 = c[2][0] - b1;
    	
    	if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    System.out.println("Yes");
    	}
    	
    	else{
    	    System.out.println("No");
    	}
    }
} 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();
    	    }
    	}
    	
    	int a1 =0;
    	
    	int b1 = c[0][0] - a1;
    	int b2 = c[0][1] - a1;
    	int b3 = c[0][2] - a1;
    	int a2 = c[1][0] - b1;
    	int a3 = c[2][0] - b1;
    	
    	if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    System.out.println("Yes");
    	}
    	
    	else{
    	    System.out.println("No");
    	}
    }
} 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();
    	    }
    	}
    	
    	int a1 =0;
    	
    	int b1 = c[0][0] - a1;
    	int b2 = c[0][1] - a1;
    	int b3 = c[0][2] - a1;
    	int a2 = c[1][0] - b1;
    	int a3 = c[2][0] - b1;
    	
    	if(a2+b2 == c[1][1] && a2 + b3 == c[1][2] && a3 + b2 == c[2][1] && a3 + b3 ==c[2][2]){
    	    System.out.println("Yes");
    	}
    	
    	else{
    	    System.out.println("No");
    	}
    }
}