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 b[] = {c[0][0] - 0, c[0][1] - 0, c[0][2] - 0};
		int a[] = {0, c[1][0] - b[0], c[2][0] - b[0]};

		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				if (c[i][j] != a[i] + b[j]) {
					System.out.println("No");
					return;
				}
			}
		}
		System.out.println("Yes");
	}
}
/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