#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;

const int INF = (1 << 30) - 1;
const ll INF64 = ((ll)1 << 62) - 1;
const double PI = 3.1415926535897932384626433832795;

const int dx[] = { -1, 0, 1, 0 };
const int dy[] = { 0, 1, 0, -1 };

int gcd(int x, int y) { return y ? gcd(y, x % y) : x; }
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }
int lcm(int x, int y) { return x / gcd(x, y) * y; }
ll lcm(ll x, ll y) { return x / gcd(x, y) * y; }

bool solve(vector<int> x) {
	for (int i = 0; i < x.size() - 1; i++) {
		if (abs(x[i] - x[i + 1]) != 1) {
			return false;
		}
	}

	return true;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	int t;
	cin >> t;

	vector<int> x;
	x.push_back(0);
	for (int i = 0; i < t; i++) {
		int pos;
		cin >> pos;
		x.push_back(pos);
	}

	cout << (solve(x) ? "T" :"F") << endl;
	return 0;
}