import java.util.*;
import java.lang.Double;

public class Main {
  
    public static void main(String[] args) {
      Scanner reader=new Scanner(System.in);
      String a=reader.nextLine();
      if(a.equals("ABC"))
      {
        System.out.println("ARC");
      }else
      {
          System.out.println("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