package yukicoder;
import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		new Main().solve();
	}
	void solve(){
		Scanner sc=new Scanner(System.in);
		//F,B,L,R
		int[][] map=new int[200][200];
		int x=50;int y=50;
		int[] dx={1,0,-1,0};
		int[] dy={0,1,0,-1};
		int d=0;
		while(true){
			int r=(int)(Math.random()*4);
			if(r==0){
				if(map[y+dy[d%4]][x+dx[d%4]]!=-1)
					System.out.println("F");
			}else if(r==1){
				if(map[y+dy[(d+2)%4]][x+dx[(d+2)%4]]!=-1)
					System.out.println("B");
			}else if(r==2){
				System.out.println("L");
				d++;
			}else if(r==3){
				System.out.println("R");
				d--;
			}
			String s=sc.nextLine();
			if(s.equals("-1")){
				map[y+dy[d%4]][x+dx[d%4]]=-1;
			}else if(r==0){
				y=y+dy[d%4];
				x=x+dx[d%4];
			}else if(r==1){
				y=y+dy[(d+2)%4];
				x=x+dx[(d+2)%4];
			}
			if(s.equals("Merry Christmas!")){
				return;
			}
		}
	}
}