Problem:
Score : 100 points

Problem Statement

On the Planet AtCoder, there are four types of bases: A, C, G and T. A bonds with T, and C bonds with G.

You are given a letter b as input, which is A, C, G or T. Write a program that prints the letter representing the base that bonds with the base b.

Constraints

b is one of the letters A, C, G and T.

Input

Input is given from Standard Input in the following format:

b

Output

Print the letter representing the base that bonds with the base b.

Sample Input 1

A

Sample Output 1

T

Sample Input 2

G

Sample Output 2

C

Solution in Ruby (2.3.3) (judge verdict: Runtime Error)

N, Q=gets.split.map(&:to_i)
S=gets.chomp
lrs=Q.times.map { gets.split.map(&:to_i) }

lrs.each do |lr|
  cnt=0
  str = S[(lr[0]-1), (lr[1]-1)]
  ((str.size)-1).times do |i|
    if str[i] == "A" || str[i+1] == "C"
      cnt+=1
    end
  end
  p cnt
end