static void Median(string[] a, int[] x)
{
    SortedBag<int> numberList = new SortedBag<int>();
    for (int i = 0; i < a.Length; i++)
    {
        var operation = a[i]; //"a" or "r"
        var operationNumber = x[i]; // integer

        if (operation == "r")
        {
            if (!numberList.Contains(operationNumber))
            {
                Console.WriteLine("Wrong!");
                continue;
            }
            else
            {
                if (numberList.Contains(operationNumber))
                numberList.Remove(operationNumber);
            }
        }
        else
        {
            numberList.Add(operationNumber);
        }
        if (numberList.Count == 0)
        {
            Console.WriteLine("Wrong!");
        }
        else if (numberList.Count % 2 == 0)
        {
            var indexToCalculate = (numberList.Count) / 2;
            decimal median = (decimal)(numberList[indexToCalculate - 1]
                + (decimal)numberList[indexToCalculate]) / 2;
            Console.WriteLine(median);
        }
        else
        {
            int indexToCalculate = 0;
            if (numberList.Count != 1)
            {
                indexToCalculate = (numberList.Count) / 2;
            }
            var median = numberList[indexToCalculate];
            Console.WriteLine(median);
        }
    }
}
public class SortedBag<T> where T : IComparable<T>
 {
     private readonly List<T> _items = new();

     public void Add(T item)
     {
         int index = _items.BinarySearch(item);
         if (index < 0) index = ~index;
         _items.Insert(index, item);
     }

     public bool Remove(T item)
     {
         int index = _items.BinarySearch(item);
         if (index < 0)
             return false;

         while (index > 0 && _items[index - 1].CompareTo(item) == 0)
             index--;

         _items.RemoveAt(index);
         return true;
     }

     public int Count => _items.Count;

     // Indexer support
     public T this[int index] => _items[index];

     public bool Contains(T item)
     {
         return _items.BinarySearch(item) >= 0;
     }
 }