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.*;
public class Main {// Main


	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int k = sc.nextInt();
		HashSet<Integer> map =new HashSet<Integer>();
		for(int i =  1 ; i<=k; i++) {
			int d = sc.nextInt();
			for(int  j = 1 ; j<=d ;j++) {
				int x = sc.nextInt();
				map.add(x);
			}
		}
		System.out.println(n - map.size());
			}

	}