import java.util.*;

class Main{
  public static void main(String[] args){
    Scanner sc=new Scanner(System.in);
    int[][] c=new int[3][3];
    int[] a=new int[3];
    int[] b=new int[3];
    for(int i=0;i<3;i++){
      for(int j=0;j<3;j++){
        c[i][j]=sc.nextInt();
      }
    }
    if(c[0][1]-c[0][0]==c[1][1]-c[1][0]&&
       c[1][1]-c[1][0]==c[2][1]-c[2][0]){
      if(c[0][2]-c[0][1]==c[1][2]-c[1][1]&&
         c[1][2]-c[1][1]==c[2][2]-c[2][1]){
        if(c[1][0]-c[0][0]==c[1][1]-c[0][1]&&
           c[1][1]-c[0][1]==c[1][2]-c[0][2]){
          if(c[2][0]-c[1][0]==c[2][1]-c[1][1]&&
             c[2][1]-c[1][1]==c[2][2]-c[1][2]){
            System.out.println("Yes");
            return;
          }
        }
      }
    }
    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