use std::io::*;
use std::str::FromStr;

fn main() {
    exec(read());
}

fn exec(i: i64) {
    println!(
        "{}",
        match i {
            1 => 0,
            _ => count_tap(i),
        }
    );
}

fn count_tap(i: i64) -> i64 {
    let i_bin = format!("{:b}", i);
    let count_pow = binary_string_len(&i_bin) - 1;
    let a = pow_two(count_pow, 1);
    if i - a == 0 {
        return count_pow;
    } else {
        count_pow + 1
    }
}

fn binary_string_len(s: &String) -> i64 {
    s.len() as i64
}

fn pow_two(i: i64, mut acc: i64) -> i64 {
    if i == 0 {
        return acc;
    } else {
        acc = acc * 2;
        pow_two(i - 1, acc)
    }
}

fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}