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: Accepted)

import java.lang.reflect.Array;
import java.text.SimpleDateFormat;
import java.util.*;

public class Main {

    private static void nCombination3(int c) {
        int count = c;
        int num = 0;
        for (int i = 0; i < count - 2; i++) {
            for (int j = i + 1; j < count - 1; j++) {
                for (int k = j + 1; k < count; k++) {
                    num++;
                }
            }
        }
    }



    public static void main(String[] args) {
        // write your code here
        Scanner sc=new Scanner(System.in);
        String S=sc.next();
        if(S.equals("ABC")){
            System.out.println("ARC");
        }else{
            System.out.println("ABC");
        }
    }
}