import java.util.*;
class Main{
  public static void main(String[] args){
    Scanner sc=new Scanner(System.in);
    int ans=0;
    int[][]nums=new int[3][3];
    for(int i=0;i<9;i++){
      nums[i/3][i%3]=sc.nextInt();
    }
    System.out.println(nums[1][0]-nums[0][0]==nums[1][1]-nums[0][1]&&nums[1][1]-nums[0][1]==nums[1][2]-nums[0][2]&&nums[2][0]-nums[1][0]==nums[2][1]-nums[1][1]&&nums[2][1]-nums[1][1]==nums[2][2]-nums[1][2]?"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