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.Collections;
using System.Collections.Generic;


public class A
{
	public static void Main()
	{
		char b = Console.ReadLine()[0];
		char result = '\0';
		switch(b)
		{
			case 'A':
				result = 'T';
				break;
				
			case 'C':
				result = 'G';
				break;
				
			case 'G':
				result = 'C';
				break;
				
			case 'T':
				result = 'A';
				break;
				
			default:
				throw new Exception();			
		}
			
		Console.WriteLine(result);
	}	
}