#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;

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

    int b = 1, y = 0;
    for (int i = 0; i < t; i++) {
        int x;
        cin >> x;
        if (abs(x - y) != 1) b = 0;
        y = x;
    }

    cout << "FT"[b] << endl;

    return 0;
}