J_f(A)= 
\begin{tabular}{|c|c|c|c|c|c|c|}
\hline
$\!\!\!\!-2\!\!\!\!$\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm}\\
\hline
\rule{3mm}{0mm}\rule{0mm}{5mm} & $\!\!\!\!-2\!\!\!\!$\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm}\\
\hline
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
$\!\!\!\!-1\!\!\!\!$\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm}\\
\hline
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & $\!\!\!\!-1\!\!\!\!$\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm}\\
\hline
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
$\!\!\!\!-1\!\!\!\!$\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm}\\
\hline
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} &
$\!\!\!\!-1\!\!\!\!$\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm}\\
\hline
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & \rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} &
\rule{3mm}{0mm}\rule{0mm}{5mm} & $\!\!\!\!-1\!\!\!\!$\rule{0mm}{5mm}\\
\hline
\end{tabular}\\
\rule{0mm}{0mm}\\\end{tabular}