fn main() {
	let mut s = String::new();
	std::io::stdin().read_line(&mut s).ok();
	let n: u64 = s.trim().parse().unwrap();
	let mut c = (n as f64).sqrt() as u64;
	if c * c > n {
		c -= 1;
	}
	let mut a = 2 * c;
	if n / c == c {
		a -= 1;
	}
	println!("{a}")
}