public class Main { static Scanner sc = new Scanner(System.in); static PrintWriter pw = new PrintWriter(System.out);
public static void main(String[] args) { double tot = 0; int n = sc.nextInt(); for (int i = 1; i <= n; i++) tot += 1. / i; pw.println(String.format("%.6f", tot)); sc.close(); pw.close(); } }