import java.util.*;
import java.io.*;

class Main {

	public static void main(String[] args) throws IOException{
		BufferedReader br =new BufferedReader(new InputStreamReader(System.in));
		String s=br.readLine();
		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