using System;

public class Program

{       

    public static double TongLuyThua(double x, int n)//B17

        {

            int i = 2;

            double Tich = x;

            double Tong = x;

            while (i <= n)

            {

                Tich *= x;

                Tong+=(Tich/i);

                i++;

            }

            return Tong;

        }

    public static void Main()

    {

        Console.WriteLine("Nhap n");

        int n=int.Parse(Console.ReadLine());                

        Console.WriteLine("Nhap x");

        double x = double.Parse(Console.ReadLine());        

        Console.WriteLine("B17: " + TongLuyThua(x,n));

    }

}