import java.io.*;

public class Main {
  
  public static void main(String[] args) throws Exception {
    
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    String[] in = br.readLine().split(" ");

    br.close();
    
    PrintWriter out = new PrintWriter(System.out);
    out.println(in[0].equals("ABC") ? "ARC" : "ABC");
    out.flush();

  }
}
/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