#include <iostream>
using namespace std;
int main()
{
	int N;
	cin >> N;
	char S;
	string ans = "Three";
	for (int i = 0; i < N; i++)
	{
		cin >> S;
		if (S=='Y')
		{
			ans = "Four";
			break;
		}
	}
	cout << ans << endl;
}