import java.util.*;
import java.io.*;
import java.math.*;
public class Main {
    public static void main(String[]args){
		Scanner sc = new Scanner(System.in);
		PrintWriter ou = new PrintWriter(System.out);
		int n = Integer.parseInt(sc.next());
		sc.close();
		double yo = 0;
		for(int i = 1 ; i <= Math.pow(10 , 6) ; i++){
			yo += 1 / Math.pow(i , n);
		}
		ou.println(yo);
		ou.flush();
	}
}