Is there any way to call the parent version of an overridden method? (C# .NET)

class ParentClass
{
    public int methodOne()
    {
        return methodTwo();
    }

    virtual public int methodTwo()
    {
        return 1;
    }
}

class ChildClass : ParentClass
{
    override public int methodTwo()
    {
        return 2;
    }
}

class Program
{
    static void Main(string[] args)
    {
        var a = new ChildClass();
        Console.WriteLine("a.methodOne(): " + a.methodOne());
        Console.WriteLine("a.methodTwo(): " + a.methodTwo());
        Console.WriteLine("((ParentClass)a).methodTwo(): "
		 + ((ParentClass)a).methodTwo());
        Console.ReadLine();
    }
}

class ChildClass : ParentClass
{
    new public int methodTwo() // bad, do not do
    {
        return 2;
    }
}