an> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">;</span>
    <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">assign</span><span class="special">;</span>

    <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span 