How to Edit Thank you message for Contact page in Magento

Some time we need to change message on magento contact success, we can do so by following steps go to
'app\code\core\Mage\Contacts\controllers'

search for 'Mage::getSingleton('customer/session')->addSuccess(Mage::helper('contacts')->__('Your inquiry was submitted and will be responded to as soon as possible. Thank you for contacting us.'));'

or go to line no 112. and change it to according to your requirment...