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] = Integer.parseInt(sc.next());
			}
		}
		sc.close();
		int[] a = new int[3];
		int[] b = new int[3];
		a[0] = 0;
		b[0] = C[0][0];
		b[1] = C[0][1];
		b[2] = C[0][2];
		a[1] = C[1][0] - b[0];
		a[2] = C[2][0] - b[0];
		String ans = "Yes";
		for(int i = 0;i < 3;i++) {
			for(int j = 0;j < 3;j++) {
				if(a[i] + b[j] != C[i][j]) {
					ans = "No";
				}
			}
		}
		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