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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

public class Main {

  public static void main(String[] args) {

    Map<String, String> base = new HashMap<>();
    base.put("A","T");
    base.put("T","A");
    base.put("C","G");
    base.put("G","C");

    String in = null;
    try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))){
      in = br.readLine();
    } catch (IOException e) {
      e.printStackTrace();
      System.exit(1);
    }

    System.out.print(base.get(in));

  }
}