import java.util.ArrayList;
import java.util.Scanner;
 class Main
{
	public static void main (String[] args)
	 {
		Scanner sc=new Scanner(System.in); 
		int t,i;
		String s=sc.next();
		if(s.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