#include<bits/stdc++.h>
using namespace std;

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

#define mygc(c) (c)=getchar_unlocked()
#define mypc(c) putchar_unlocked(c)

#define ll long long
#define ull unsigned ll

void reader(int *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);}
void reader(ll *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);}
void reader(double *x){scanf("%lf",x);}
int reader(char c[]){int i,s=0;for(;;){mygc(i);if(i!=' '&&i!='\n'&&i!='\r'&&i!='\t'&&i!=EOF) break;}c[s++]=i;for(;;){mygc(i);if(i==' '||i=='\n'||i=='\r'||i=='\t'||i==EOF) break;c[s++]=i;}c[s]='\0';return s;}
template <class T, class S> void reader(T *x, S *y){reader(x);reader(y);}
template <class T, class S, class U> void reader(T *x, S *y, U *z){reader(x);reader(y);reader(z);}
template <class T, class S, class U, class V> void reader(T *x, S *y, U *z, V *w){reader(x);reader(y);reader(z);reader(w);}

void writer(int x, char c){int s=0,m=0;char f[10];if(x<0)m=1,x=-x;while(x)f[s++]=x%10,x/=10;if(!s)f[s++]=0;if(m)mypc('-');while(s--)mypc(f[s]+'0');mypc(c);}
void writer(ll x, char c){int s=0,m=0;char f[20];if(x<0)m=1,x=-x;while(x)f[s++]=x%10,x/=10;if(!s)f[s++]=0;if(m)mypc('-');while(s--)mypc(f[s]+'0');mypc(c);}
void writer(double x, char c){printf("%.15f",x);mypc(c);}
void writer(const char c[]){int i;for(i=0;c[i]!='\0';i++)mypc(c[i]);}
void writer(const char x[], char c){int i;for(i=0;x[i]!='\0';i++)mypc(x[i]);mypc(c);}
template<class T> void writerLn(T x){writer(x,'\n');}
template<class T, class S> void writerLn(T x, S y){writer(x,' ');writer(y,'\n');}
template<class T, class S, class U> void writerLn(T x, S y, U z){writer(x,' ');writer(y,' ');writer(z,'\n');}
template<class T> void writerArr(T x[], int n){int i;if(!n){mypc('\n');return;}rep(i,n-1)writer(x[i],' ');writer(x[n-1],'\n');}

char memarr[17000000]; void *mem = memarr;
#define MD 1000000007

int x, y, d;
char mp[100][100];

char vis[100][100][4];

int dx[4] = {-1,1,0,0}, dy[4] = {0,0,-1,1};

void print(const char c[]){
  puts(c);
  fflush(stdout);
}


#define INF 1000000000

int dist[100][100];
int st[10000], sts;

void get_dist(int x, int y){
  int i, j, k, ni, nj;

  rep(i,100) rep(j,100) dist[i][j] = INF;
  dist[x][y] = 0;
  st[0] = x*100+y; sts=1;
  while(sts){
    k = st[--sts];
    i = k/100; j = k%100;
    rep(k,4){
      ni = i + dx[k];
      nj = j + dy[k];
      if(mp[ni][nj]!='.') continue;
      if(dist[ni][nj]==INF) dist[ni][nj] = dist[i][j], st[sts++] = ni * 100 + nj;
    }
  }
}

int main(){
  int i, j, k;
  char buf[1000];
  int nx, ny;
  int cnt = 0;

  rep(i,100) rep(j,100) mp[i][j] = '?';
  x = y = 50;
  mp[x][y] = '.';

  for(;;){
    gets(buf);
    if(buf[0]=='M') break;
    k = atoi(buf);

    if(k>=20000){
      print("F");
      continue;
    }

    vis[x][y][d] = 1;
    
    nx = x; ny = y;
    rep(i,k){
      mp[nx][ny] = '.';
      nx += dx[d];
      ny += dy[d];
    }
    mp[nx][ny] = '#';

    rep(k,4) if(vis[x][y][k]==0) break;
    if(k!=4){
      print("L");
      continue;
    }

    rep(i,100) rep(j,100) if(vis[i][j][0]==0) nx = i, ny = j;
    get_dist(nx, ny);
    if(dist[i][j] > dist[i+dx[d]][j+dy[d]]){
      print("F");
      continue;
    }
    print("L");
  }

  return 0;
}