Smarties Candy

I really like Smarties candy, and lately, I've been indulging myself by allowing them into my diet. This stuff:
I like to open the roll and eat them two at a time, by color. Two orange, two green, etc. Here's the really weird thing though:
There are always three singles left over.
They aren't always the same colors, either, because any Smarties eater knows those rolls are pretty random. But in any given roll, all the colors can be eaten in pairs, and there will be three candies left over, in three colors. Always three. It's really strange.

UPDATE:
I did some math on this, and here's the thing: I think there are 6 colors the candies come in. There's an odd number of candies in each roll, and that means that the only possible numbers of leftover candies are 1, 3, and 5. So technically, 1 and 5 should show up regularly as well. Now, I think I HAVE gotten only 1 on one or two occasions, I must admit, but really, mostly only 3.