Traversing to a specific child element with Prototype

Given the following markup. ``` <div id="example"> <div> <div> <input type='hidden'></input> </div> </div> </div> ``` How can I quickly get the hidden input element given I have the ID for the top most div element with the ID 'example'? I can hack away at it so I can just iterate through each child element until I hit the input, however, I'd like to improve on that and utilize Prototype and simply jump to that hidden input given the div. Thanks!