class NotEnoughStockException:Exception
    {
        public override string ToString()
        {
            return "Not Enough Stock";
        }
    }

    class SalesItem
    {
        string name;
        int stock;
        public SalesItem(string Name,int Stock)
        {
            this.name = Name;
            this.stock = Stock;
        }
        public void Sell(int Qty)
        {
            if (Qty > stock)
                throw new NotEnoughStockException();

            stock -= Qty;
        }
        public void Show()
        {
            Console.WriteLine("{0} :{1}Kg",name,stock);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                SalesItem i = new SalesItem("Dal", 10);
                i.Show();
                i.Sell(5);
                i.Show();
                i.Sell(13);
                i.Show();
            }
            catch (NotEnoughStockException e)
            {
                Console.WriteLine("There was an error!");
                Console.WriteLine(e);
            }
        }
    }
}