CalculateSum

// 05. Write a program that, for a given two integer numbers n and x, calculates the sum S = 1 + 1!/x + 2!/x2 + … + n!/xn.
// Use only one loop.
// Print the result with 5 digits after the decimal point.
using System;

class CalculateSum
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        int x = int.Parse(Console.ReadLine());
        double sum = 1;
        double factorial = 1;

        for (int i = 1; i <= n; i++)
        {
            factorial = factorial * i;
            sum += factorial / Math.Pow(x, i);
        }

        Console.WriteLine("{0:#.00000}", sum);
    }
}