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_A
{
	internal class Program
	{
		public static void Main(string[] args)
		{
			string input = Console.ReadLine();

			if (input == "A")
			{
				Console.WriteLine("T");
			}else if (input == "T")
			{
				Console.WriteLine("A");
			}else if(input == "C")
				Console.WriteLine("G");
			else Console.WriteLine("C");
				
			
		}
	}
}