// No.627 ランダムウォークの軌跡
// https://yukicoder.me/problems/no/627
//

#include <iostream>
using namespace std;
char solve(int T);

int main() {
    int T;
    cin >> T;
    char res = solve(T);
    cout << res << endl;
}

char solve(int T) {
    int prev;
    cin >> prev;
    if (prev != 1 && prev != -1)
        return 'F';
    
    int current;
    for (auto i = 1; i < T; i++) {
        cin >> current;
        if (current != prev+1 and current != prev-1)
            return 'F';
        prev = current;
    }
    return 'T';
}