Problem:
Score : 200 points

Problem Statement

You are given a string s consisting of lowercase English letters. Extract all the characters in the odd-indexed positions and print the string obtained by concatenating them. Here, the leftmost character is assigned the index 1.

Constraints

Each character in s is a lowercase English letter.

1≤|s|≤10^5

Input

The input is given from Standard Input in the following format:

s

Output

Print the string obtained by concatenating all the characters in the odd-numbered positions.

Sample Input 1

atcoder

Sample Output 1

acdr

Extract the first character a, the third character c, the fifth character d and the seventh character r to obtain acdr.

Sample Input 2

aaaa

Sample Output 2

aa

Sample Input 3

z

Sample Output 3

z

Sample Input 4

fukuokayamaguchi

Sample Output 4

fkoaaauh

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

#include <stdio.h>
#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <cctype>
#include <cmath>
#include <cstdlib>
#include <iomanip>
#include <algorithm>
#include <string.h>
#include <memory.h>

using namespace std;

typedef long long ll;
int const N = 1e2 + 1, oo = 2e9 + 1;
int n, m, q, k, a[N];
vector<vector<int> > g;

int main() {
	string s;
	cin >> s;
	for(int i = 0; i < s.length(); ++i)
		if(i % 2 == 0)
			cout << s[i];
	cout << endl;

    return 0;
}