	import java.util.*;
	import java.util.Map.Entry;
	 
	 
	 class Main {
		 static int mod =  (int) (Math.pow(10,9)+7);
		 static List<ArrayList<Integer>>  list = new ArrayList<ArrayList<Integer>>();
	    public static void main(String[] args) {
	    	
	        Scanner sc = new Scanner(System.in);
	        String S = sc.next();	
	        if(S.equals("ABC")) {
	        	System.out.println("ARC");
	        } else {
	        	System.out.println("ABC");
	        }
	        
	        
	        long ans=0;
	        
	    }
	}
/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