primes in range with list

   class Primes
    {
        static void Main(string[] args)
        {

            List<int> primes = new List<int>(); // we keep here all primes from the first one to the 251th
            int number = 2; // the number we start from

            int position1 = 24; // could be read from console
            int position2 = 101; // could be read from console
            int position3 = 251; // could be read from console

            while (primes.Count <= position3) // primes list count <= maxNumberFromInput e.g. 251
            {
                bool isCurrentNumberPrime = true; // assert the number is prime, until we find the opposite

                for (int divider = 2; divider <= Math.Sqrt(number); divider++)
                {
                    if (number % divider == 0) // if the number is divisble to any number from 2 to its root, it's certainly not prime
                    {
                        isCurrentNumberPrime = false;
                        break; // we have determined that the number is not prime, we don't need to try to divide to any number anymore. Exit the loop
                    }
                }


                if (isCurrentNumberPrime) // if the number hasn't divided to any number from the previous loop, the boolean variable will stay "true"
                {
                    primes.Add(number); // add the already determined prime number to our primes collection
                }

                number++; // go to the next number to check if it's prime again
            }

            Console.WriteLine(primes[position1 - 1]);
            Console.WriteLine(primes[position2 - 1]);
            Console.WriteLine(primes[position3 - 1]);
            Console.WriteLine("----");
            Console.WriteLine(primes[128]); // for sanity check let's try to find thr 127th prime
        }

    }