import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

class Main {



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




    }


}
/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