import java.util.Scanner;
public class Main {
  enum Event {
  ARC,
  ABC
}
	public static void main (String[] args) {
		Scanner in = new Scanner(System.in);
		String h = in.nextLine();
      System.out.println(nextEvent(h));
    }
   static Event nextEvent(String event){
            if(Event.valueOf(event).equals(Event.ARC))
            {
              return Event.ABC ;
            }else{
                  return Event.ARC ;
            }
		}
	}
/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