import java.util.*;

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