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: Wrong Answer)

def trans(s)
  s.split('').map { |c|
    case c
      when 'A' then 'T'
      when 'T' then 'A'
      when 'G' then 'C'
      when 'C' then 'G'
    else 'X'
    end
    }.join
end

b = readline
puts trans(b)