#include <bits/stdc++.h>

using namespace std;

int main() {
    int t;
    cin >> t;

    vector<int> x(t + 1);
    x[0] = 0;
    for (int i = 1; i <= t; ++i) {
        cin >> x[i];
    }

    for (int i = 0; i < t; ++i) {
        if (abs(x[i + 1] - x[i]) != 1) {
            cout << "F" << endl;
            return 0;
        }
    }

    cout << "T" << endl;
    return 0;
}