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

#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
#include<fstream>
#include<utility>
#include<bitset>
#include<map>
#include<deque>
#include<cmath>
#include<random>
#include<string.h>
#define FOR(i, a, b) for (int i = a; i < b; ++i)
#define rep(N) for (int i = 0; i < N; ++i)
#define Rep(a, b) for (int i = a; i < b; ++i)
#define For(i, N) for (int i = 0; i < N; ++i)
#define all(v) v.begin(), v.end()
#define rev(v) v.rbegin(), v.rend()
#define makei(N) int N; cin >> N;
#define makel(N) ll N; cin >> N;
#define makes(s) string s; cin >> s;
#define maked(d) double d; cin >> d;
#define makev(v, N) vi v(N); rep(N)cin >> v[i];
#define mod 1000000007
#define re return 0

using namespace std;
using ll = long long int;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vector<bool>>;
using vs = vector<string>;
using pii = pair<int, int>;
using pis = pair<int, string>;
using msi = map<string, int>;

template<typename T>
void say(T s) {
	cout << s << "\n";
}

template<typename T>
void say(vector<T> s) {
	auto itr = s.begin();
	cout << *(itr++);
	while (itr != s.end()) {
		cout << " " << *(itr++);
	}
	cout << "\n";
}

int main() {
  makes(s1);
  makes(s2);
  makes(s3);
  cout<<s1[0]<<s2[1]<<s3[2]<<endl;
}