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# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Text;

namespace AtCorder
{
    class Program
    {
        static void Main(string[] args)
        {
            var s = Console.ReadLine();
            var length = s.Length;
            var sb = new StringBuilder();

            for (var i = 0; i < length; i++)
            {
                if (i % 2 != 0)
                {
                    continue;
                }

                sb.Append(s[i]);
            }

            Console.WriteLine(sb.ToString());
        }
    }
}