You are camping at night and are about to go out for a walk.
You have a flashlight with no batteries in it.
You realize you are carrying 8 batteries out of which only 4 are charged batteries and the other 4 are uncharged.
The flashlight needs 2 charged batteries to work.
You do not know which batteries are charged and which ones are not.
What is the least number of attempts to make the flashlight work?
(An attempt consists of putting two batteries in the flashlight and checking if the flashlight works or not.)