static bool IsPrime(BigInteger Num) // podstawowy
        {
            OpDivision = 0;
            {
                if (Num < 2) return false;
                else if (Num < 4) return true;
                else if (Num % 2 == 0)
                {
                    OpDivision++;
                    return false;
                }
                else for (BigInteger u = 3; u < Num / 2; u += 2)
                        if (Num % u == 0)
                        {
                            OpDivision++;
                            return false;
                        }
                        else return true;
            }
            Console.WriteLine(OpDivision);
        }