import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskC solver = new TaskC();
        solver.solve(1, in, out);
        out.close();
    }

    static class TaskC {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int[][] c = new int[3][3];
            for (int i = 0; i < 3; i++) for (int j = 0; j < 3; j++) c[i][j] = in.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];

            String ans = "Yes";
            for (int i = 0; i < 3; i++) {
                for (int j = 0; j < 3; j++) {
                    if (c[i][j] != a[i] + b[j]) {
                        ans = "No";
                        break;
                    }
                }
            }

            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