#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define mem(a) memset(a,0,sizeof(a))
#define pd(a) printf("%.10f\n",a)
#define pb(a) push_back(a)
#define in(a) insert(a)
#define pi M_PI
#define R cin>>
#define F first
#define S second
#define C class
#define ll long long
#define ln cout<<'\n'
#define _(_1,_2,_3,N,...)N
#define pr(...) _(__VA_ARGS__,pr3,pr2,pr1)(__VA_ARGS__)
template<C T>void pr1(T a){cout<<a;ln;}
template<C T,C T2>void pr2(T a,T2 b){cout<<a<<' '<<b;ln;}
template<C T,C T2,C T3>void pr3(T a,T2 b,T3 c){cout<<a<<' '<<b<<' '<<c;ln;}
template<C T>void PR(T a,int n){rep(i,n){if(i)cout<<' ';cout<<a[i];}ln;}
bool check(int n,int m,int x,int y){return x>=0&&x<n&&y>=0&&y<m;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,1,0,-1};
typedef pair<int,int> P;

void Main() {
  int a[100][100],u[100][100][4];
  memset(a,-1,sizeof(a));mem(u);
  int x=50,y=50,k=0;
  stack<int> st;
  while(1) {
    u[x][y][k]=1;
    a[x][y]=1;
    string s;
    R s;
    if(s[0]=='M') break;
    else if(s=="20151224") {
      x+=dx[k],y+=dy[k];
      pr('F');
    } else {
      stringstream ss;
      ss << s;
      int t;
      ss >> t;
      REP(i,1,t+2) {
        int xx=x+dx[k]*i,yy=y+dy[k]*i;
        if(i<=t) a[xx][yy]=1;
        else a[xx][yy]=0;
      }
      int kk=(k+1)%4;
      int xx=x+dx[k],yy=y+dy[k];
      if(!u[x][y][kk]) {
        pr("R");
        st.push(1);
        k=kk;
      } else if(a[xx][yy]==1&&!u[xx][yy][k]) {
        pr("F");
        st.push(0);
        x=xx,y=yy;
      } else {
        int z=st.top();st.pop();
        if(!z) {
          pr("B");
          x=x+dx[(k+2)%4],y=y+dy[(k+2)%4];
        } else {
          pr("L");
          k=(k+3)%4;
        }
      }
    }
    cout.flush();
  }
}

int main() {
  ios::sync_with_stdio(0);cin.tie(0);
  Main();return 0;
}