jquery child selection

<div id="pp">
       <div>
           1</div>
       <div>
           2</div>
       <div>
           3</div>
       <div>
           4</div>
       <div>
           5</div>
       <div>
           6</div>
   </div>
   <input type="button" id="removediv" value="remove" />

<script type="text/javascript">
        $('#removediv').click(function () {
            $("div#pp").contents().not('div:last-child').remove();
        });
</script>