import java.util.*;

public class Main {
    public static void main(String[] args)  {
        Scanner scan = new Scanner(System.in);
        int[][] c = new int [3][3];
        for (int i = 0;i < 3; ++i){
            for (int k = 0;k < 3; ++k){
                c[i][k] = Integer.parseInt(scan.next());
            }
        }

        int[] x = new int [3];
        int[] y = new int [3];

        for (int i = 0;i < 3; ++i){
            y[i] = c[0][i]-x[0];
        }

        for (int i = 0;i < 3; ++i){
            x[i] = c[i][0]-y[0];
        }

        for (int i = 0;i < 3; ++i){
            for (int k = 0;k < 3; ++k){
                if (c[i][k] != x[i]+y[k]){
                    System.out.println("No");
                    return;
                }
            }
        }

        System.out.print("Yes");
    }
}
/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