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

    let bitsize: usize = format!("{:b}", n).len() - 1;

    println!("{}", bitsize + if n % 2usize.pow(bitsize as u32) > 0 { 1 } else { 0 });
}