nofollow Drupal Theme

Ivan, hello, I downloaded the template theme, and it has links to Twitter and Facebook. I'm opening page.tpl, and in it, the link is:

<li><a href="http://www.twitter.com/<?php echo theme_get_setting('twitter_username'); ?>" target="_blank" rel="me"><img src="<?php global $base_url; echo $base_url.'/'.$directory; ?>/images/twitter.png" alt="twitter"/></a></li>

how can I make it nofollow

I tried like this, but it didn't work....

<li><a href="http://www.twitter.com" rel="nofollow"><?php echo theme_get_setting('twitter_username'); ?>" target="_blank" rel="me"><img src="<?php global $base_url; echo $base_url.'/'.$directory; ?>/images/twitter.png" alt="twitter"/></a></li>