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.Generic;
using static System.Console;
using System.Linq;

namespace ConsoleApp2
{
    class Program {
        static void Main(string[] Args) {
            Dictionary<string, string> dictionary = new Dictionary<string, string>();
            dictionary.Add("A", "T");
            dictionary.Add("T", "A");
            dictionary.Add("C", "G");
            dictionary.Add("G", "C");

            WriteLine(dictionary[ReadLine()]);

            ReadLine();
        }
    }
}