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: Accepted)

x = ["A", "T"]
y = ["C", "G"]
b = gets.chomp.to_s
if x.include?(b)
  x.delete(b)
  puts x[0]
else
  y.delete(b)
  puts y[0]
end