Install f.lux on Ubuntu 13.10

Now if you try to follow instructions on http://justgetflux.com/linux.html you will fail at step

sudo apt-get update

because there is no such url http://ppa.launchpad.net/kilian/f.lux/ubuntu/dists/saucy/main/binary-i386/Packages today (02.11.2013) for Ubuntu 13.10 (saucy). Edit in Software & Updates distribution to raring and continue with fillowings

sudo apt-get update 

sudo apt-get install fluxgui

Thats all.