fn main() {
    let stdin = std::io::read_to_string(std::io::stdin()).unwrap();
    let mut stdin = stdin.split_ascii_whitespace();

    let t: usize = stdin.next().unwrap().parse().unwrap();
    let x: Vec<i8> = (0..t)
        .map(|_| stdin.next().unwrap().parse().unwrap())
        .collect();

    println!("{}", output(solve(x)));
}

fn solve(x: Vec<i8>) -> bool {
    x[0].abs() == 1 && x.windows(2).all(|x| x[0].abs_diff(x[1]) == 1)
}

fn output(ans: bool) -> &'static str {
    match ans {
        true => "T",
        false => "F",
    }
}