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)

## https://qiita.com/naotospace/items/8edea2f89566d0f687ec

# ハッシュを使う
b = gets.chomp.to_s

hash = {A: "T", T: "A", C: "G", G: "C"}

puts hash[b]