using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Numerics;

namespace _6.SumCalculation

{

    public class SumCalculation

    {

        private static BigInteger FindFactorial(int N)

        {

            BigInteger factorial=1;

            for (int i = 1; i < N+1; i++)

            {

                factorial = factorial * i;

            }

            return factorial;

        }

        private static BigInteger FindPower(int X,int N)

        {

            BigInteger powerX=1;

            for (int i = 1; i < N + 1; i++)

            {

                powerX = powerX *X;

            }

            return powerX;

        }

        public static void Main()

        {

            int N, X;

            double sum=1.0;

            Console.Write("Enter the first number N:");

            bool isNInt = int.TryParse(Console.ReadLine(), out N);

            Console.Write("Enter the second number X:");

            bool isXInt = int.TryParse(Console.ReadLine(), out X);

            if (isNInt && isXInt)

            {

                for (int i = 1; i < N+1; i++)

                {

                    sum = sum + ((double)FindFactorial(i) / (double)FindPower(X, i));

                }

                Console.WriteLine("sum={0}", sum);

            }

            else

            {

                Console.WriteLine("Not a valid entry!");

            }

        }

    }

}