import java.util.*;

public class Main {
    public static void main(String[] args) {
        try (Scanner s = new Scanner(System.in)) {
            System.out.println(s.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