How to reset Available Software Sites to factory defaults in Eclipse Luna?

Question

Probably I have a problem with Eclipse software sites. So, I went to software sites and delete all of them:

Now, how to enter default sites here?

Note, that I don't want to mottle them one by one.

Answer 1

Only those 2 I think :

http://download.eclipse.org/releases/luna/

http://download.eclipse.org/eclipse/updates/4.4

source