#include <bits/stdc++.h>

using namespace std;

int main()
{
	int n;
	cin >> n;
	set<char> s;
	char c;
	for (int i = 0; i < n; i++)
		cin >> c, s.insert(c);
	cout << (s.size() > 3 ? "Four" : "Three") << endl;
	return 0;
}
