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 abc122a{
  static void Main(){
    var b = Console.ReadLine();
    var result = "";
    if(b.Equals("A"))result="T";
    if(b.Equals("C"))result="G";
    if(b.Equals("G"))result="C";
    if(b.Equals("T"))result="A";
    
    Console.WriteLine(result);
    return;
  }
}