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