We've been talking about a five-operation \emph{agenda} ADT for the last
few classes,
which is an important idea but not quite present in the Java
libraries.  In this problem, you'll adapt
existing library code into a more abstract framework.

First, write the \class{Agenda<T>} interface.  It should require five
methods: \code{isEmpty}, \code{size}, \code{add}, \code{remove}, and
\code{peek}.

Then, write two classes \class{MyStack<T>} and
\class{MyQueue<T>} that implement that interface using, respectively,
a LIFO policy and a FIFO policy.
Code re-use is key here; all the real algorithm
work is already done, and your only job for this problem is to 
\emph{adapt} it for use in this framework.

Remember, you're using the Java libraries in this problem.  Don't try to
use \class{ListNode}!
