How to select 2 minimum number of file upload ?

Hello all. I have question. How to select 2 minimum number of file upload ? im using CMultiFileUpload widget.

as yoou see there is possible to select for max number of file upload. but i couldnt find for minimum number of file upload.


 <?php 

			$this->widget('CMultiFileUpload', array(

                'model'		=> $model,

                'attribute'	=> 'images',

                'accept' 	=> 'gif|jpg|png', 

                'max'		=> NUM_PICS_UPLOAD,

                'selected'  => 'shekil secildi',

                'duplicate' => 'Duplicate file!', 

                'denied' 	=> 'Invalid file type',

                'htmlOptions' => array('tabindex' => 17)

            ));

			?>