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)

# 英小文字からなる文字列 s が与えられます。
# 前から数えて奇数文字目だけ抜き出して作った文字列を出力してください。
# ただし、文字列の先頭の文字を1文字目とします。
# 前から数えて奇数文字目だけ抜き出して作った文字列を出力せよ。
a_s = gets.chomp.split("")

odd_a_s = []
a_s.each_index do |idx|
  next if idx%2 != 0
  odd_a_s << a_s[idx]
end

puts "#{odd_a_s.join}"