/* https://yukicoder.me/problems/89 */
use std::io;

fn main() {
    let mut input = String::new();
    io::stdin().read_line(&mut input).unwrap();
    let mut n: u32 = input.trim().parse().unwrap();
    let mut c = 0;
    while n > 2u32.pow(c) { c += 1}
    println!("{:?}", c);
}