import java.util.*;
import java.io.*;
public class Main{

     public static void main(String []args) throws IOException{
       
       BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
       
       String a = br.readLine();
       
       if(a.compareTo("ABC") == 0)
       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