#[macro_export]
macro_rules! setup {
    { mut $input:ident: SplitWhitespace $(,)? } => {
        use std::io::Read;
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).unwrap();
        let mut $input = buf.split_whitespace();
    };
}

#[macro_export]
macro_rules! parse_next {
    ($str_iter:expr) => {
        $str_iter.next().unwrap().parse().unwrap()
    };
}

fn main() {
    setup! { mut input: SplitWhitespace };

    let n: usize = parse_next!(input);

    let ans = match n {
        1 => 0,
        _ => {
            let mut i = 1;
            loop {
                if (2 as usize).pow(i as u32) >= n {
                    break (i - 1) + 1;
                }
                i += 1;
            }
        }
    };

    println!("{}", ans);
}