How To Use LightDM Instead Of MDM In Linux Mint 13

A few days ago, we've posted an article on how to install MDM (Mint Display Manager) in Ubuntu, and according to the comments, some Linux Mint users don't like MDM and further more, there's a bug and MDM crashes for some users, so here's the reverse too: how to use LightDM instead of MDM in Linux Mint 13 "Maya".