\begin{Schunk}
\begin{Sinput}
 z <- x + y
 z
\end{Sinput}
\begin{Soutput}
[1] 5 4 6 0 4
\end{Soutput}
\begin{Sinput}
 z <- x - y
 z
\end{Sinput}
\begin{Soutput}
[1]  3  0 -4  0  2
\end{Soutput}
\end{Schunk}
