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);
		
	}
}



/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz