import java.util.*;
public class Main{
public static void main(String[]args){
Scanner sc=new Scanner(System.in);
  int c[][]=new int[3][3];
  for(int i=0;i<3;i++){
  for(int j=0;j<3;j++){
  c[i][j]=sc.nextInt();
  }
  }
  for(int i=0;i<3;i++){
  for(int j=0;j<3;j++){
  c[i][2-j]-=c[i][0];
  }
  }
  if(c[0][1]==c[1][1]&&c[0][1]==c[2][1]&&c[0][2]==c[1][2]&&c[0][2]==c[2][2])
    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