n>
<span class="special">{</span>
    <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">()(</span><span class="keyword">int</span> <span class="identifier">x</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">x</span> <span class="special">%</span> <span class="number">2</span> <span class="special">==</span> <span class="number">0</span><span class="spe