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: Runtime Error)

#include<bits/stdc++.h>
using namespace std;

int main(){
  string S;
  
  cin>>S;
  
  int K;
  
  if(S.size()%2==0){
    K=S.size()/2;
  }
  else if(S.size()%2!=0){
    K=S.size()/2+1;
  }
  
  vector<char> ans(K);

  
  for(int i=0;i<S.size();i++){
if(i%2!=0){
  ans.at(i)=S.at(i);
}
  }
  
  for(int i=0;i<K;i++){
cout<<ans.at(i);
  }
}