#include <iostream>

using namespace std;

int t;
int x[110];

int main() {
    cin.tie(NULL);
    ios_base::sync_with_stdio(false);
    
    cin >> t;
    
    int pos;
    
    cin >> pos;
    
    if (abs(pos) != 1) {
        cout << 'F' << endl;
        return 0;
    }
    
    t--;
    
    while (t--) {
        int a;
        cin >> a;
        if (abs(pos - a) > 1 || pos == a) {
            cout << 'F' << endl;
            return 0;
        }
        pos = a;
    }
    
    cout << 'T' << endl;
}