sudo add-apt-repository ppa:gnome3-team/gnome3
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install gnome-session
sudo apt-get dist-upgrade
sudo apt-get upgrade
sudo apt-get install gnome-shell
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install gnome-session
sudo apt-get dist-upgrade
sudo apt-get upgrade
sudo apt-get install gnome-shell