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: Runtime Error)

using System;

    class Program
    {
        static void Main(string[] args)
        {
            // get a char
            char a = Convert.ToChar(args[0]);
            char val;
            if (a == 'A')
                val = 'T';
            else if (a == 'T')
                val = 'A';
            else if (a == 'C')
                val = 'G';
            else
                val = 'C';
            //output
            Console.WriteLine(val);
        }
    }