
import java.util.*;

public class Main {
    static Scanner scanner;
    public static void main(String[] args) {
        scanner = new Scanner(System.in);
        new ABC166A().main();
    }
    static class ABC166A {
        public void main()
        {
            System.out.println(scanner.next().equals("ABC")?"ARC":"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