<span class=special>(</span><span class=keyword>unsigned</span> <span class=keyword>long</span><span class=special>)(</span><span class=identifier>r</span><span class=special>.</span><span class=identifier>y1</span><span class=special>-</span><span class=identifier>r</span><span class=special>.</span><span class=identifier>y0</span><span class=special>)*(</span><span class=identifier>r</span><span class=special>.</span><span class=identifier>y1</span><span class=special>-</span><span class=identifier>r</spa