task 7

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Enter to numbers to satisfy K and N. 1< N< K");
            Console.WriteLine("K:");
            int K = int.Parse(Console.ReadLine());
            Console.WriteLine("N:");
            int N = int.Parse(Console.ReadLine());

            if (K < N || N < 1 || K<1)
            {
                Console.WriteLine("Something went wrong! This does not satisfy the condition! ");
                return;

            }

            int factorial = 1;
            for (int i = K - N + 1; i <= K; i++)
            {
                factorial *= i;

                if (i == K)
                {
                    i = 2;

                    while (i <= N)
                    {
                        factorial *= i;
                        i++;
                    }
                    break;
                }
            }
            Console.WriteLine("\n The factorial is: {0}!*{1}!/{1}-{0} = {2}\n", N, K, factorial);
        }
    }
}