题解 | #牛牛学数列2#

public class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int a = scan.nextInt();
        double sum = 0.0;
        for(int i = 1; i <= a; i++){
            sum += 1.0/i;
        }
        System.out.println(String.format("%.6f",sum));
    }
}