#include<bits/stdc++.h>
using namespace std;

int main(){

  string a,b,c;

  cin>>a;
  cin>>b;
  cin>>c;

  cout<<a.at(0)<<b.at(1)<<c.at(2)<<endl;

}
### Prompt

Your task is to create a Cpp solution to the following problem:

We have a 3×3 square grid, where each square contains a lowercase English letters. The letter in the square at the i-th row from the top and j-th column from the left is c_{ij}.

Print the string of length 3 that can be obtained by concatenating the letters in the squares on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.

Constraints

* Input consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:


c_{11}c_{12}c_{13}
c_{21}c_{22}c_{23}
c_{31}c_{32}c_{33}


Output

Print the string of length 3 that can be obtained by concatenating the letters on the diagonal connecting the top-left and bottom-right corner of the grid, from the top-left to bottom-right.

Examples

Input

ant
obe
rec


Output

abc


Input

edu
cat
ion


Output

ean

### Response

```cpp
#include<bits/stdc++.h>
using namespace std;

int main(){

  string a,b,c;

  cin>>a;
  cin>>b;
  cin>>c;

  cout<<a.at(0)<<b.at(1)<<c.at(2)<<endl;

}
```