Problem:
Score : 100 points

Problem Statement

AtCoder Inc. holds a contest every Saturday.

There are two types of contests called ABC and ARC, and just one of them is held at a time.

The company holds these two types of contests alternately: an ARC follows an ABC and vice versa.

Given a string S representing the type of the contest held last week, print the string representing the type of the contest held this week.

Constraints

S is ABC or ARC.

Input

Input is given from Standard Input in the following format:

S

Output

Print the string representing the type of the contest held this week.

Sample Input 1

ABC

Sample Output 1

ARC

They held an ABC last week, so they will hold an ARC this week.

Solution in Java (OpenJDK 11.0.6) (judge verdict: Runtime Error)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
	
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine().split(" ")[0]);
		boolean[] hasSnack = new boolean[N];
		
		while (sc.hasNextLine()) {
			sc.nextLine();
			for (String snk : sc.nextLine().split(" ")) {
              int snki = Integer.parseInt(snk) - 1;
              if (hasSnack[snki])
              	continue;
              N--;
			  hasSnack[snki] = true;
            }
		}
		
		System.out.println(N);
	
	}

}