% \begin{frame}{Exercise}
%   (Groups of two, 2 minutes)
%   \begin{exampleblock}{}
%     Construct a context-free grammar for the following NPDA.\\
%     The stack starting symbol is $z=0$.
%     \medskip
% 
%     \begin{center}
%       \input{tikz/npda1.tex}
%     \end{center}
%     
%     Use the grammar to show that $aabb$ is in the language.
%   \end{exampleblock}
% \end{frame}

\themex{Deterministic Pushdown Automata}