pan class="op">(</span></span>
<span>    cl2 <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/factor.html" class="external-link">factor</a></span><span class="op">(</span><span class="va">cl2</span><span class="op">)</span>,</span>
<span>    cl3 <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/factor.html" class="external-link">factor</a></span><span class="op">(</span><span class="va">cl3</span><span class="op">)</span>,</span>
<span>    cl4 <span class="