fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();

    let nval = format!("{:b}", n);
    if nval.chars().filter(|&c| c == '0').count() > 0 {
        println!("O");
    } else {
        println!("X");
    }
}