$output = preg_replace("/(http:\/\/|(www\.))(([^\s<]{4,68})[^\s<]*)/", '<a href="http://$2$3" rel="nofollow">Odkaz</a>', $input);
$output = preg_replace("/(http:\/\/|(www\.))(([^\s<]{4,68})[^\s<]*)/", '<a href="http://$2$3" rel="nofollow">Odkaz</a>', $input);