How to load extended core system classes from controller?

[eluser]helloworld7[/eluser]
I'm doing exactly from this page. I create my own MY_Input which extends CI_Input. I put MY_Input in application/core directory.

http://ellislab.com/codeigniter/user-gui...asses.html

I just wonder how I can use it from my controller. I will use it in all controllers so I try to put it inside autoload.php

$autoload['libraries'] = array('My_Input');

But when I do this inside my controller it fails with this message.


An Error Was Encountered

Unable to load the requested class: my_input

How can I use MY_Input? Thanks.