import java.util.*;
import java.io.*;
 
public class Main{
 
	public static void main(String[] $){
		Scanner s = new Scanner(System.in);
        String S = s.next();
        String A = "ABC";
        
        if(S.equals(A)){
            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