span class="o">=</span> <span class="mi">0</span>

  <span class="k">do </span><span class="n">concurrent</span><span class="p">(</span><span class="n">i</span> <span class="o">=</span> <span class="mi">2</span><span class="p">:</span><span class="n">idm</span><span class="o">-</span><span class="mi">1</span><span class="p">,</span><span class="n">j</span> <span class="o">=</span> <span class="mi">2</span><span class="p">:</span><span class="n">jdm</span><span class="o">-</span><span class="mi">1</span><spa