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.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws IOException {
        OutputStream outputStream = System.out;
        PrintWriter out = new PrintWriter(outputStream);
        FastReader in = new FastReader();
        test a=new test();
        a.solve(in,out);
        out.close();
    }
}
class test{
    public void solve(FastReader in, PrintWriter out){
       String s =in.next();
       if(s.equals("ABC")){
           out.println("ARC");
       }else{
           out.println("ABC");
       }
    }

}

class FastReader{
    BufferedReader br;
    StringTokenizer st;

    public FastReader(){
        br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next(){
        while(st==null || !st.hasMoreElements()){
            try{
                st=new StringTokenizer(br.readLine());
            }
            catch(IOException e){
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }

    int nextInt(){
        return Integer.parseInt(next());
    }

    Long nextLong(){
        return Long.parseLong(next());
    }

    double nextDouble(){
        return Double.parseDouble(next());
    }
    String nextLine(){
        String str="";
        try{
            str=br.readLine();
        }
        catch(IOException e){
            e.printStackTrace();
        }
        return str;
    }
}