fn main() {
    let n = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        line.trim().parse::<u64>().unwrap()
    };

    let calc_parity = |digit: u32| {
        let n = n + 1;
        let exp2 = 1 << digit;
        let lough_one_num = n / (2 * exp2) * exp2;
        let fine_one_num = (n % (2 * exp2)).saturating_sub(exp2);

        (lough_one_num + fine_one_num) % 2 == 1
    };

    let ans = (0..32).any(calc_parity);
    println!("{}", if ans { "O" } else { "X" });
}