using System;

namespace _8._Factorial_Division
{
    class Program
    {
        static void Main(string[] args)
        {
            long fact = long.Parse(Console.ReadLine());
            long devision = long.Parse(Console.ReadLine());
            long sum = fact;

            double num1 = GetFactorial(fact);
            double num2 = GetFactorial(devision);

            Console.WriteLine($"{num1 / num2:f2}");
        }

        private static double GetFactorial(long number)
        {
            for (long i = number-1; i >= 1; i--)
            {
                number = number * i;
            }

            return number;
        }
    }
}