<span class="o">-</span><span class="mi">1</span><span class="p">)[</span><span class="mi">0</span><span class="p">]</span> <span class="o">-</span> <span class="mi">1</span>

    <span class="k">for</span> <span class="n">i</span><span class="p">,</span> <span class="p">(</span><span class="n">st</span><span class="p">,</span> <span class="n">en</span><span class="p">)</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="nb">zip</span><span class="p">(</sp