#include <cstdio>
#include <cstring>
#include <string>
#include <iostream>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
bool e;
bool used[50][50];
int dx[4]={1, 0, -1, 0}, dy[4]={0, 1, 0, -1};
void dfs(int x, int y, int k){
	used[x][y]=1;
	int d;
	cin>>d;
	for(int i=0; i<4; i++){
		if(d==20151224){
			while(1){
				cout<<"F"<<endl;
				string s;
				cin>>s;
				if(s=="Merry"){
					cin>>s;
				    e=1;
				    return;
				}
			}
		}
		if(d && !used[x+dx[(k+i)&3]][y+dy[(k+i)&3]]){
			cout<<"F"<<endl;
			dfs(x+dx[(k+i)&3], y+dy[(k+i)&3], (k+i)&3);
			if(e) return;
			cout<<"B"<<endl;
			cin>>d;
		}
		cout<<"L"<<endl;
		cin>>d;
	}
}
int main()
{
	dfs(21, 21, 0);
	return 0;
}