Add buttons to MCE

MCE

<?php
function add_more_buttons($buttons) {
 $buttons[] = 'hr';
 $buttons[] = 'del';
 $buttons[] = 'sub';
 $buttons[] = 'sup';
 $buttons[] = 'fontselect';
 $buttons[] = 'fontsizeselect';
 $buttons[] = 'cleanup';
 $buttons[] = 'styleselect';
 return $buttons;
}
add_filter("mce_buttons_3", "add_more_buttons");