Community Auth - problem

Hallo ,

test admin user pass successfully .
But when I was redirect to \examples\login , I have this error message :

A PHP Error was encountered
Severity: Notice
Message: Use of undefined constant LOGIN_PAGE - assumed 'LOGIN_PAGE'
Filename: config/routes.php
Line Number: 55


My ROUTES.PHP:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');
$route['default_controller'] = 'welcome';
$route['404_override'] = '';
$route['translate_uri_dashes'] = FALSE;
$route[LOGIN_PAGE] = 'examples/login';


I don't know what is wrong ?

Thanks.

Martin