#include <bits/stdc++.h>
using namespace std;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    bool b = true;
    int n;
    int p = 0;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int t;
        cin >> t;
        if (abs(p - t) != 1) {
            b = false;
            break;
        }
        p = t;
    }
    cout << (b ? 'T' : 'F') << endl;
    return 0;
}