import java.util.*;
import static java.lang.Math.*;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		
		// 入力
		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();
		    }
		}
		
		// 計算
		String result = "No";
		for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		}
		
		// 出力
		System.out.println(result);
		
	}
}

 import java.util.*; util.* java import static java.lang.Math.*; import static java.lang.Math.*; import static java.lang.Math.*; public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		
		// 入力
		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();
		    }
		}
		
		// 計算
		String result = "No";
		for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		}
		
		// 出力
		System.out.println(result);
		
	}
} Main public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		
		// 入力
		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();
		    }
		}
		
		// 計算
		String result = "No";
		for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		}
		
		// 出力
		System.out.println(result);
		
	} main {
		Scanner sc = new Scanner(System.in);
		
		// 入力
		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();
		    }
		}
		
		// 計算
		String result = "No";
		for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		}
		
		// 出力
		System.out.println(result);
		
	} 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 result = "No"; result "No" for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		} int a1 = -200; int a1 = -200; a1 -200 200 a1 <= 200 a1 200 a1++ a1++ a1 {
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		} {
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		} boolean bool = true; bool true 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(c[1][1] != a2 + b2) bool = false; c[1][1] != a2 + b2 c[1][1] c[1] c 1 1 a2 + b2 a2 b2 bool = false bool false if(c[1][2] != a2 + b3) bool = false; c[1][2] != a2 + b3 c[1][2] c[1] c 1 2 a2 + b3 a2 b3 bool = false bool false if(c[2][1] != a3 + b2) bool = false; c[2][1] != a3 + b2 c[2][1] c[2] c 2 1 a3 + b2 a3 b2 bool = false bool false if(c[2][2] != a3 + b3) bool = false; c[2][2] != a3 + b3 c[2][2] c[2] c 2 2 a3 + b3 a3 b3 bool = false bool false if(bool){
		        result = "Yes";
		        break;
		    } bool {
		        result = "Yes";
		        break;
		    } result = "Yes" result "Yes" break; System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		
		// 入力
		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();
		    }
		}
		
		// 計算
		String result = "No";
		for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		}
		
		// 出力
		System.out.println(result);
		
	}
} public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		
		// 入力
		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();
		    }
		}
		
		// 計算
		String result = "No";
		for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		}
		
		// 出力
		System.out.println(result);
		
	}
} Main
import java.util.*;
import static java.lang.Math.*;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		
		// 入力
		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();
		    }
		}
		
		// 計算
		String result = "No";
		for(int a1 = -200; a1 <= 200; a1++){
		    boolean bool = true;
		    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(c[1][1] != a2 + b2) bool = false;
		    if(c[1][2] != a2 + b3) bool = false;
		    if(c[2][1] != a3 + b2) bool = false;
		    if(c[2][2] != a3 + b3) bool = false;
		    if(bool){
		        result = "Yes";
		        break;
		    }
		}
		
		// 出力
		System.out.println(result);
		
	}
}


