import java.util.*;

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();
			}
		}

		for(int i=0; i<=100; i++){
			int a = i;
			int b1 = c[0][0] - i;
			int b2 = c[0][1] - i;
			int b3 = c[0][2] - i;

			if(c[1][0] - b1 == c[1][1] - b2 && c[1][1] - b2 == c[1][2] - b3){
				if(c[2][0] - b1 == c[2][1] - b2 && c[2][1] - b2 == c[2][2] - b3){
					System.out.println("Yes");
					return;
				}
			}
		}
		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