#include<bits/stdc++.h>
using namespace std;
int main()
{
int n,c=0;
cin >> n;
char a;
while(n--){
  cin >>a;
  if(a=='Y'){
    c++;
  }
}
if(c>0){
cout << "Four" << endl;
  
}else{
  cout << "Three" << endl;
}
}
