import java.util.*;

public class Main
{
	public static  void main(String args[])
	{
		Scanner scan = new Scanner(System.in);
		String w1 = scan.nextLine();
		String w2="ABC";
		if(w1.equals(w2))
		{
			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