#include <iostream>
using namespace std;

int main() {
	int n, p = 0, x;
	cin >> n;
	char res = 'T';

	for (int t = 0; t<n; t++) {
		cin >> x;
		if (x == p || abs(p - x) != 1)res = 'F';
		p = x;
	}
	cout << res <<endl;
	return 0;
}