#include <iostream>

using namespace std;

int main () {
	int n;
	cin >> n;
	int *x = new int[n + 1];
	x[0] = 0;
	for (int i = 1; i < n + 1; ++i) cin >> x[i];

	bool valid = true;
	for (int i = 1; i < n + 1; ++i) {
		if (x[i] != x[i - 1] - 1 && x[i] != x[i - 1] + 1) {
			valid = false;
			break;
		}
	}

	cout << (valid ? "T" : "F") << endl;

}