import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        System.out.println("Wtite Number");
        Scanner in = new Scanner(System.in);
        int NumberOfValues = in.nextInt();
        double Result = 0;
        double Dividend = 1;
        double Divider = 7;
        for(int i=0;i<NumberOfValues;i++){
            Result = Result + (Dividend/Divider);
            Dividend++;
            Divider = Divider + 2;
        }
        System.out.println("Result = " + Result);
    }
}