import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		int[][] a=new int[3][3];
		int[] x=new int[3];
		int[] y=new int[3];
		Scanner sc=new Scanner(System.in);
		for(int i=0;i<3;i++) {
			for(int j=0;j<3;j++) {
				a[i][j]=sc.nextInt();
			}
			
		}
		boolean flag=true;
		
			for(int k=0;k<100;k++) {
				x[0]=k;
				for(int i=0;i<3;i++) {
					y[i]=a[0][i]-x[0];
				}
				for(int i=0;i<3;i++) {
					x[i]=a[i][0]-y[0];
				}
				flag=true;
				for(int i=0;i<3;i++) {
					for(int j=0;j<3;j++) {
						if(x[i]+y[j]!=a[i][j]) {
							flag=false;
							break;
						}
					}
					
				}
				if(flag) {
					break;
				}
				
			}
			
			
		
		
		if(flag) {
			System.out.println("Yes");
		}
		else{
				System.out.println("No");
			}
		
	}

}

/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