import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Main {



    private static final Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
       String s = sc.next();
       if (s.equals("ABC") )
       System.out.println("ARC");
       else 
       System.out.println("ABC");

        //scanner.close();
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz