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)

b = gets

if b == nil then
  exit
else
  b = b.chomp
end

def putOther(arg1, arg2, targetnum)
  if arg1 == targetnum then
    puts arg2
  else
    puts arg1
  end
end

ar1 = ["A", "T"]
ar2 = ["C", "G"]

if ar1.include?(b) then
  putOther(ar1[0], ar1[1], b)
else
  putOther(ar2[0], ar2[1], b)
end