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 Python (3.4.3) (judge verdict: Accepted)

import sys, os
import collections

def solve(input_stream):
  table = {
    "A": "T",
    "T": "A",
    "C": "G",
    "G": "C"
  }
  ans = ""
  for i in input_stream.readline().strip():
    ans += table[i]
  return [ans]

if __name__ == "__main__":
    outputs = solve(sys.stdin)
    for line in outputs:
      print(line)