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.io.*;

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    
    String b = br.readLine()
            .replaceAll("A", "t")
            .replaceAll("T", "a")
            .replaceAll("C", "g")
            .replaceAll("G", "c")
            .toUpperCase();
    
    System.out.println(b);
  }
}