import java.util.*;

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;
        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];
        boolean isYes = true;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (c[i][j] != a[i] + b[j]) {
                    isYes = false;
                }
            }
        }
        System.out.println(isYes ? "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