N!K!

using System;
// Write a program that calculates N!*K! / (K-N)! for given N and K (1<N<K).

class Calculates
{
    static void Main()
    {
        Console.WriteLine("Enter N : ");
        int numN = int.Parse(Console.ReadLine());

        Console.WriteLine("Enter K : ");
        int numK = int.Parse(Console.ReadLine());

        int numKN = (numK - numN); // (K-N)

        if (numN > 1 && numN < numK)
        {
            for (int i = 1, j = numN, n = 1; i <= j; i++) // Just test capabilities on for
            {
                n *= i;
                if (numKN == i)
                {
                    numKN = n;
                }
                if (numK == i)
                {
                    numK = n;
                }
                if (numN == i)
                {
                    numN = n;
                }
            }
            Console.WriteLine(numKN);
            Console.WriteLine("{0}",((numN*numK)/(numKN*1.0)));
        }
        else
        {
            Console.WriteLine(" 1<K<N ");
        }
    }
}