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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
public class Main {
	public static void main(String[] args){
		// get numbers
		Scanner sc = new Scanner(System.in);        
		String b = sc.next();
        String ans = "";

        if (b.equals("A")) {
            ans = "T";
        } else if (b.equals("T")) {
            ans = "A";
        } else if (b.equals("C")) {
            ans = "G";
        } else {
            ans = "C";
        }

		// output
        System.out.println(ans);
        sc.close();
	}
}