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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

        using System;
        using System.Linq;
 
        public class Program
        {
            public static void Main(string[] args)
            {
            	string input = Console.ReadLine();
            Console.WriteLine(input == "A" ? "T": input == "T" ? "A": input == "C" ? "G" : input == "G" ? "C": "NO");            }
        }