\item \ifassignmentsheet \points{3}
  \dpllDescriptionAssignmentSheet
\else \prac
  \dpllDescription{negative}
\fi

\begin{dpllCNFInput}
    \item $\{a,b,c\}$
    \item $\{\neg a,b\}$
    \item $\{\neg b,c\}$
    \item $\{\neg c, d\}$
    \item $\{\neg c, e\}$
    \item $\{\neg d,\neg e\}$
\end{dpllCNFInput}