class CalculatesTheSumS
{
    static void Main()
    {
        long n = long.Parse(Console.ReadLine());
        long x = long.Parse(Console.ReadLine());
        double sequenceMember = 1;
        double sum = 1; 

        for (int i = 1; i <= n; i++)
        {
            sequenceMember *= (double)i / x;
            sum += sequenceMember;
        }

        Console.WriteLine("{0:F5}",sum);
      
    }
}