Playing with beer caps

Here is a simple game you can play with some beer caps of various colors. It's very simple but fun to play it alone against yourself to match or better your best score; otherwise you can play it in a tournament with as many people as you want.

This is what you need:
-20 beer caps of ten different colors (10 pairs)
-a table or just a flat surface that can fit the caps in five columns of four caps with some gap between raws and columns.

How to play:

Mix the caps well and sort them out randomly on the table in five columns of four caps. You can swap two caps that are next to each other, left with right or top with bottom. Count your moves until you reach one of the configurations in which all the pairs of caps of the same color are formed.

Here is a sequence of three moves:

Got it? Now go for it... do your best!