Change Unity to Gnome on ubuntu 12.04

Here some step to change Unity to Gnome.

1. Add repository

sudo add-apt-repository ppa:gnome3-team/gnome3 

2. Run repository update

sudo apt-get update

3. Install the gnome-shell

sudo apt-get install gnome-shell

4. Log out than login, but remember to choose the session first ... and Enter... violaaa... your gnome desktop ready to use...