use std::io::*; use std::str::*; fn read(sl: &mut StdinLock) -> Option { let s = sl.by_ref().bytes().map(|c| c.unwrap() as char) .skip_while(|c| c.is_whitespace()) .take_while(|c| !c.is_whitespace()) .collect::(); s.parse::().ok() } fn run(sl: &mut StdinLock) { let n = read::(sl).unwrap(); let r = (0..).try_fold(1, |acc, i| { if acc < n { Ok(acc * 2) } else { Err(i) } }); println!("{}", r.err().unwrap()); } fn main() { let s = stdin(); let mut sl = s.lock(); run(&mut sl); }