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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;
using static System.Console;
using static System.Math;
 
public class Hello{
    public static void Main(){
/*        string[] input = ReadLine().Split(' ');
        int n = int.Parse(input[0]);
        int m = int.Parse(input[1]);*/
//        int b = int.Parse(input[2]);
//        string temp = ReadLine();
//        int a = int.Parse(ReadLine());
        string temp = ReadLine();
        for(int i=0;i<temp.Length;i++){
            if(i%2==0){
                Write(temp[i]);
            }
        }
        WriteLine();
    }
}