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];

        a[0] = 0;
        for (int i = 0; i < 3; i++) b[i] = c[0][i] - a[0];
        for (int i = 0; i < 3; i++) a[i] = c[i][0] - b[0];

        boolean good = true;

        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (a[i] + b[j] != c[i][j]) good = false;
            }
        }

        System.out.println(good ? "Yes" : "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