#[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() }; } use std::collections::VecDeque; fn main() { setup! { mut input: SplitWhitespace }; let n: usize = parse_next!(input); let ans = (|| { let mut queue = VecDeque::new(); let mut visited = vec![false; n * 2]; let mut depth = 0; { queue.push_back(1); visited[1 - 1] = true; } while !queue.is_empty() { for _ in 0..queue.len() { let i = queue.pop_front().unwrap(); if i == n { return depth + 1; } let i_ones = i.count_ones() as usize; let mut children = vec![]; { let j = i + i_ones; if 1 <= j && j <= n { children.push(j); } } { if !(i <= i_ones) { let j = i - i_ones; if 1 <= j && j <= n { children.push(j); } } } for j in children.into_iter() { if !visited[j - 1] { queue.push_back(j); visited[j - 1] = true; } } } depth += 1; } return -1; })(); println!("{:?}", ans); }