#include<iostream>
#include<vector>
using namespace std;
int main() {
	int T;
	cin >> T;
	vector<int> X(T);
	for (int i = 0; i < T; i++) {
		cin >> X[i];
	}
	if (X[0] != 1 && X[0] != -1) {
		cout << 'F' << endl;
		return 0;
	}
	for (int i = 0; i < T - 1; i++) {
		if (X[i] != X[i + 1] + 1 && X[i] != X[i + 1] - 1) {
			cout << 'F' << endl;
			return 0;
		}
	}
	cout << 'T' << endl;
}