pan><span class="p">(</span><span class="n">iy</span><span class="p">)</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">xi</span><span class="p">(</span><span class="n">ix</span><span class="p">)</span><span class="o">*</span><span class="n">yr</span><span class="p">(</span><span class="n">iy</span><span class="p">)</span>
<span class="w">         </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">s</span><span class="