\begin{frame}{Exercise (1)}
  \begin{exampleblock}{}
    Let $M$ be the following DFA:
    \begin{center}
      \input{tikz/dfa_even_bs.tex}
    \end{center}    
    Describe the language accepted by $M$.
    \pause\bigskip
    
    \emph{Answer:}
    \begin{itemize}
      \item []
        $L(M)$ consists of all words over the alphabet $\{\,a,b\,\}$ that contain an even number of $b$'s.
    \end{itemize}
  \end{exampleblock}
\end{frame}