Problem:
Score : 100 points

Problem Statement

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.

Sample Input 1

ant
obe
rec

Sample Output 1

abc

The letters in the squares on the diagonal connecting the top-left and bottom-right corner of the grid are a, b and c from top-right to bottom-left. Concatenate these letters and print abc.

Sample Input 2

edu
cat
ion

Sample Output 2

ean

Solution in JavaScript (node.js v5.12) (judge verdict: Runtime Error)

const fs = require('fs');
const input = fs.readFileSync(stdin);
const range = input.toString().split(" ");
const min = parseInt(range[0]);
const max = parseInt(range[1]);
let result = 0;
for(let i = min; i < max; i++) {
  const s = i.toString();
  if(s[0] == s[4] && s[1] == s[3]) result++;
}
console.log(result);