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 Scala (2.11.7) (judge verdict: Time Limit Exceeded)

import scala.io.{StdIn => in}

object Main extends App {
  val ans = in.readLine().toCharArray()./:("", 0) { (acc, ch) =>
    if(acc._2 % 2 == 0) (acc._1 + ch, acc._2 + 1) else (acc._1, acc._2 + 1)
  }._1
  println(ans)
}