#include <bits/stdc++.h>
using namespace std;
 
int main() {
  int N, y = 0;
  char S;
  cin >> N;
  for(int i = 0; i < N; i++){
    cin >> S;
    if(S == 'Y')
      y++;
  }
  cout << (y == 0 ? "Three" : "Four") << endl;
} 