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 Ruby (2.3.3) (judge verdict: Accepted)

# https://qiita.com/mnuma/items/22338399a86064c61f24

s = gets.split("")

ans = "" # 空を渡しておく　[]配列を渡すとおかしくなる

N = s.length

N.times do |i|
  if i % 2 == 0
    ans << s[i]  # 配列で自信の末尾に破壊的に値を追加
  end
end

puts ans