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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.io.IOException;
import java.util.Arrays;
import java.util.Scanner;
 
public class Main {
 
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    String B = sc.nextLine();
    int max = 0;
    int count = 0;
    for(int i=0; i<B.length(); i++) {
      if(B.charAt(i) == 'A' || B.charAt(i) == 'C' || B.charAt(i) == 'G' || B.charAt(i) == 'T') {
        count++;
      } else {
        
        max = Math.max(max, count);
        count = 0;
      }
    }
    max = Math.max(max, count);
    System.out.println(max);
  }
}