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;
class Program
{
  static void Main(string[] args)
  {
    string S = Console.ReadLine();
    string A,T,G,C;
    A = "A";
    T = "T";
    G = "G";
    C = "C";
    
    if(S == A) Console.WriteLine("T");
    else if(S == T) Console.WriteLine("A");
    else if(S == G) Console.WriteLine("C");
    else if(S == C) Console.WriteLine("G");
  }
}