#[allow(unused_macros)]
pub mod input {
    macro_rules! value {
        ($iter:expr, ($($type: tt),*)) => {
            ($(input::value!($iter, $type)),*);
        };
        ($iter: expr, [$type: tt; $len: expr]) => {
            (0..$len).map(|_| input::value!($iter, $type)).collect::<Vec<_>>()
        };
        ($iter: expr, Chars) => {
            input::value!($iter, String).chars().collect::<Vec<_>>>()
        };
        ($iter: expr, $type: ty) => {
            if let Some(v) = $iter.next() {
                v.parse::<$type>().ok()
            } else {
                None
            }
        };
    }

    macro_rules! expand {
        ($iter: expr,) => {};
        ($iter: expr, mut $var: ident : $type: tt, $($xs: tt)*) => {
            let mut $var = value!($iter, $type);
            input::expand!($iter, $($xs)*);
        };
        ($iter: expr, $var: ident : $type: tt, $($xs: tt)*) => {
            let $var = input::value!($iter, $type);
            input::expand!($iter, $($xs)*);
        };
    }

    macro_rules! read_line {
        ($($xs: tt)*) => {
            let mut buf = String::new();
            std::io::stdin().read_line(&mut buf).unwrap();
            let mut iter = buf.split_whitespace();
            input::expand!(iter, $($xs)*);
        };
    }

    #[allow(unused_imports)]
    pub(super) use {expand, read_line, value};
}

fn main() {
    input::read_line! {
        n: usize,
    }
    let n = n.unwrap();

    println!(
        "{}",
        if (1..=n).fold(0, |x, y| x ^ y) != 0 {
            "O"
        } else {
            "X"
        }
    );
}