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 Haskell (GHC 7.10.3) (judge verdict: Accepted)

{-# LANGUAGE BangPatterns          #-}

import Control.Monad
import Control.Applicative
import Data.List as List
import Data.Set as Set



solve:: Int -> String -> String
solve _ [] = ""
solve i (x:xs)
    | (mod i 2) == 0 = solve (i + 1) xs
    | otherwise = [x] ++ (solve (i + 1) xs) 

main :: IO()
main = do
    s <- getLine
    let a = solve 1 s
    putStrLn a