import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long n = sc.nextLong();
        long idx = (long)Math.sqrt(n);
        if (n / idx > n / (idx + 1)) {
            idx++;
        }
        long prev = 0;
        System.out.println(idx + n / idx - 1);
    }
}