Problem:
Score: 300 points

Problem Statement

We have a 3 \times 3 grid. A number c_{i, j} is written in the square (i, j), where (i, j) denotes the square at the i-th row from the top and the j-th column from the left.

According to Takahashi, there are six integers a_1, a_2, a_3, b_1, b_2, b_3 whose values are fixed, and the number written in the square (i, j) is equal to a_i + b_j.

Determine if he is correct.

Constraints

c_{i, j} \ (1 \leq i \leq 3, 1 \leq j \leq 3) is an integer between 0 and 100 (inclusive).

Input

Input is given from Standard Input in the following format:

c_{1,1} c_{1,2} c_{1,3}
c_{2,1} c_{2,2} c_{2,3}
c_{3,1} c_{3,2} c_{3,3}

Output

If Takahashi's statement is correct, print Yes; otherwise, print No.

Sample Input 1

1 0 1
2 1 2
1 0 1

Sample Output 1

Yes

Takahashi is correct, since there are possible sets of integers such as: a_1=0,a_2=1,a_3=0,b_1=1,b_2=0,b_3=1.

Sample Input 2

2 2 2
2 1 2
2 2 2

Sample Output 2

No

Takahashi is incorrect in this case.

Sample Input 3

0 8 8
0 8 8
0 8 8

Sample Output 3

Yes

Sample Input 4

1 8 6
2 9 7
0 7 7

Sample Output 4

No

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>

using namespace std;

int main(){
  int c[3][3];

  for(int i=0;i<3;i++){
    for(int j=0;j<3;j++){
      cin>>c[i][j]; 
    } 
  }

  for(int i=0;i<2;i++){
    for(int j=0;j<2;j++){
      if((c[i][j]-c[i+1][j])!=(c[i][j+1]-c[i+1][j+1])){
        cout<<"No"<<endl;
        return 0;
      }
    }
  }
  for(int i=0;i<2;i++){
    if((c[0][i]-c[2][i])!=(c[0][i+1]-c[2][i+1])){
      cout<<"No"<<endl; 
      return 0;
    } 
  }

  for(int i=0;i<2;i++){
    for(int j=0;j<2;j++){
      if((c[j][i]-c[j][i+1])!=(c[j+1][i]-c[j+1][i+1])){
        cout<<"No"<<endl; 
        return 0;
      } 
    } 
  }

  for(int i=0;i<2;i++){
    if((c[i][0]-c[i][2])!=(c[i+1][0]-c[i+1][2])){
      cout<<"No"<<endl;
      return 0;
    }
  }

  cout<<"Yes"<<endl;

  return 0;
}