Routes regular expressions?

Hello. I wanted to make a routing with a regular expression that allows for number range 100 - 672 (100, 101, 102 ... 671, 672). I tried this example, for Numbers range 100 - 699.
How can I change this?
Thanks for your help.

routes.php

PHP Code:

$route['default_controller'] = 'welcome';
$route['404_override'] = '';
$route['translate_uri_dashes'] = FALSE;

// http://localhost:8888/domain/text-text-text/123
// Now only for Numbers  range 100 - 699
$route['(:any)/([1-6][0-9][0-9])'] = "category/index/$1";