import java.util.Scanner;
public class Main {
    public static void main(String args[]) {
        Scanner s = new Scanner(System.in);
        String ans = "ABC";
        String str = s.next();
        if ("ABC".equals(str)) {
            ans = "ARC";
        }
        System.out.println(ans);
    }
}

/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