

import java.util.Scanner;

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();
			}
		}

		String ans = "No";

		if (c[0][0] - c[1][0] == c[0][1] - c[1][1] && c[0][0] - c[1][0] == c[0][2] - c[1][2])
			if (c[0][0] - c[2][0] == c[0][1] - c[2][1] && c[0][0] - c[2][0] == c[0][2] - c[2][2])
				if (c[1][0] - c[2][0] == c[1][1] - c[2][1] && c[1][0] - c[2][0] == c[1][2] - c[2][2])
					if (c[0][0] - c[0][1] == c[1][0] - c[1][1] && c[0][0] - c[2][1] == c[0][0] - c[2][1])
						if (c[0][0] - c[0][2] == c[1][0] - c[1][2] && c[0][0] - c[0][2] == c[2][0] - c[2][2])
							if (c[0][1] - c[0][2] == c[1][1] - c[1][2] && c[0][1] - c[0][2] == c[2][1] - c[2][2])
								ans = "Yes";

		System.out.println(ans);

	}

}

/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