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 Rust (1.15.1) (judge verdict: Accepted)

use std::io::*;

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn main() {
    diagonal_string();
}

fn diagonal_string() {
    let c1: String = read();
    let c2: String = read();
    let c3: String = read();
    let c1v = c1.chars().collect::<Vec<char>>();
    let c2v = c2.chars().collect::<Vec<char>>();
    let c3v = c3.chars().collect::<Vec<char>>();
    println!("{}{}{}", c1v[0], c2v[1], c3v[2]);
}