<map id="D" name="D">
<area shape="rect" id="node1" title=" " alt="" coords="22,171,61,197"/>
<area shape="rect" id="node4" href="$class_c.html" title=" " alt="" coords="50,260,89,287"/>
<area shape="rect" id="node2" href="$class_a.html" title=" " alt="" coords="50,5,89,32"/>
<area shape="rect" id="node3" href="$class_b.html" title=" " alt="" coords="53,95,92,121"/>
</map>
