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 <bits/stdc++.h>
#define PI 3.1415926535897
using namespace std;
typedef long long ll;
const int INF = 1000000000;
const ll LINF = 1000000000000000000; //1e18
const double EPS = 1e-10;            //

int main(void)
{
    string S;
    cin >> S;

    for (int i = 0; i < S.size(); i++)
    {
        if (i % 2 == 0)
        {
            printf("%c", S[i]);
        }
    }
    printf("\n");
    return (0);
}