use std::io::stdin;
pub fn main() {
    let n: usize = {
        let mut s = String::new();
        let _ = stdin().read_line(&mut s);
        s.trim().parse().unwrap()
    };
    if n == 1 {
        println!("0");
    } else {
        for i in 1..1000 {
            if n <= 2 << i - 1 {
                println!("{}", i);
                break;
            }
        }
    }
}