adv03.rs

use std::cmp;

fn spiral_distance(num: u32) -> u32 {
	let ring = (((num as f64).sqrt() - 1.) / 2.).ceil() as u32;
	let root = (num as f64 - 1.).sqrt() as u32;
	let offset_to_mid = root / 2;
	let ring_min = root * root + 1 + offset_to_mid;
	let ring_max = (root + 1) * (root + 1) - offset_to_mid;
	return ring + cmp::min(
		(num as i32 - ring_min as i32).abs(),
		(num as i32 - ring_max as i32).abs()) as u32;
}

fn main() {
	let mut digits_string = String::new();
	std::io::stdin().read_line(&mut digits_string).expect("wtf?");
	let num = digits_string.trim().parse::<u32>().unwrap();
	println!("{}", spiral_distance(num));
}