SubClassing in C#

sample.cs

    public class Shape
    {
        virtual public int GetHeight()
        {
            return 101;
        }
    }

    public class Square : Shape
    {
        public int GetWidth()
        {
            return 23;
        }

        // Is this is correct way to override?
        override public int GetHeight()
        {
            return 202;
        }
    }

    /*
     * var box = new Square();
     * var height = box.GetHeight();
     * var width = box.GetWidth();
     */