using System;

public class Program

{

    public static void Main()

    {

        int i, n;

        double s = 0.0;

        Console.Write("Nhap so phan tu: ");

        n = Convert.ToInt32(Console.ReadLine());

            Console.Write("\n\n");

            for (i = 1; i <= n; i++)

            {

                if (i < n)

                {

                    Console.Write("1/{0} + ", i);

                }

                else {

                    Console.Write("1/{0}", i);

                }

                s += 1 / (float)i;

            }

            Console.Write(" het qua {0} la {1} ", n, s);            

​

    }

}