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;

namespace ABC122
{
    class Program
    {
        static int Main(string[] args)
        {
            Program.ProblemA();
                return 0;

        }

        static void ProblemA()
        {
            string input = Console.ReadLine();
            string output;
            if(input == "A")
            {
                output = "T";
            }
            else if(input == "T")
            {
                output = "A";
            }
            else if(input == "C")
            {
                output = "G";
            }
            else
            {
                output = "C";
            }
            Console.WriteLine(output);
        }
    }
}