Calculate N! / K!

using System;


class CalculateFactorialNDividedFactorialK
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine()); ;
        int k = int.Parse(Console.ReadLine()); ;
        long product = 1;

        for (int i = (k+1); i <= n; i++)
        {
            product *= i;
        }

        Console.WriteLine(product);
    }
}