package writer;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

public class RandomCrawler {
	static Scanner in;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		Random gen = new Random(0);
		while(true){
			String input = in.next();
			if(input.charAt(0) >= '0' && input.charAt(0) <= '9'){
				if(input.equals("20151224")){
					out.println("F");
					out.flush();
					continue;
				}
			}else{
				break;
			}
			char command = "FBLR".charAt(gen.nextInt(4));
			out.println(command);
			out.flush();
		}
	}
	
	public static void main(String[] args) throws Exception
	{
		in = INPUT.isEmpty() ? new Scanner(System.in) : new Scanner(INPUT);
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
	}
	
	static int ni() { return Integer.parseInt(in.next()); }
	static long nl() { return Long.parseLong(in.next()); }
	static double nd() { return Double.parseDouble(in.next()); }
	static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}