import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int c11 = sc.nextInt();
        int c12 = sc.nextInt();
        int c13 = sc.nextInt();
        int c21 = sc.nextInt();
        int c22 = sc.nextInt();
        int c23 = sc.nextInt();
        int c31 = sc.nextInt();
        int c32 = sc.nextInt();
        int c33 = sc.nextInt();
        
        int diff21 = c21 - c11;
        int diff31 = c31 - c11;
        
        if (c22 - c12 == diff21 && c23 - c13 == diff21 &&
            c32 - c12 == diff31 && c33 - c13 == diff31) {
            System.out.println("Yes");
        } else {
            System.out.println("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