List array removed and append the last in c#

class Program

    {

        static void Main(string[] args)

        {

            List<string> list1 = new List<string>();

            // list elements

            list1.Add("A");

            list1.Add("I");

            list1.Add("G");

            list1.Add("B");

            list1.Add("E");

            list1.Add("H");

            list1.Add("F");

            list1.Add("C");

            list1.Add("D");

            list1.Add("a");

            list1.Add("--Geen--");

            Console.WriteLine("Original List");

            List<string> list2 = new List<string>();

            for (int i = 0; i < list1.Count; i++)

            {

                if (list1[i].Contains("--Geen--"))

                {

                    list2.Add(list1[i]);

                    list1.RemoveAt(i);

                }

            }

            list1.Add(list2[0]);

            Console.WriteLine("\nSorted List");

            // use of List.Sort() method

            list1.Sort(StringComparer.Ordinal);

        }

    }