题解 | #牛牛学数列2#

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        double sum = 0;
        while(n != 0) {
            sum = sum + (1.0 / n);
            n--;
        }
        System.out.printf("%.6f", sum);
    }
}