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();
			}
		}

		int a[] = new int[3];
		int b[] = new int[3];

		boolean ans = false;

		for (int n = 0; n <= c[0][0]; n++) {
			a[0] = n;
			b[0] = c[0][0] - a[0];
			b[1] = c[0][1] - a[0];
			b[2] = c[0][2] - a[0];

			a[1] = c[1][0] - b[0];
			a[2] = c[2][0] - b[0];

			loop: for (int i = 0; i < 3; i++) {
				for (int j = 0; j < 3; j++) {
					if(c[i][j] == a[i] + b[j]) {
						ans = true;
					} else {
						ans = false;
						break loop;
					}
				}
			}
		}
		if (ans) {
			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