use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let mut a = Vec::new();
    let mut bit = n;
    while bit > 0 {
        a.push(bit);
        bit = (bit - 1) & n;
    }
    a.sort();
    println!("{}", a[a.len() / 2]);
}