How to remove gnome from login screen after uninstalling gnome shell

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http://askubuntu.com – I tried gnome-shell but didn't quite like it. After removing gnome-shell, I still have them in login menu. However, upon logging in with any gnome option, I get to the usual Unity desktop. I had purged gnome-shell using apt-get, but seems like some component is still remaining. How do I remove gnome login options from lightdm login screen? (HowTos)