#include<iostream>
using namespace std;
int main(){
  int a,count=0;
  char b;
  cin>>a;
  for(int i=0;i<a;i++){
    cin>>b;
    if(b=='Y')
      count++;
  }
  if(count>0)
    cout<<"Four"<<endl;
  else
    cout<<"Three"<<endl;
}