Hello! Which item do you need the most?
I would love to have the Firewood the most. 
Unfortunately I need firewood the most too. How about I take 2 firewood, 2 food, and 1 water?
I feel that I am not getting a fair deal. 
Then what do you think is fair?
I think that I should get 2 firewood, 1 food and 2 water
I will let you have 2 firewood if you let me have 3 food, 2 water, and 1 firewood.
That would leave me with no food. I counter with 2 firewood 1 food 1 water. 
Well, with the extra firewood you are getting you will be able to cook your own food.
So to recap the deal is that I will get 2 firewood, 0 food, and 1 water