#include <bits/stdc++.h>

using namespace std;


int main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int n, t;
    vector <int> v;

    cin >> n;

    v.push_back(0);
    for (int i = 0; i < n; i++)
    {
        cin >> t;
        v.push_back(t);
    }

    for (int i = 1; i <= n; i++)
    {
        if (abs(v[i] - v[i - 1]) != 1)
        {
            cout << "F" << '\n';
            return 0;
        }
    }

    cout << "T" << '\n';
    return 0;
}