More of a math question...

[DustyPorViva]

Okay, say I have a number of directions, in this example, 16.
I have a set dir1, 6.
And I also have dir2, 1.

How would I get the 'distance', or in this case, the number of directions dir1 is from dir2?
I know in the example I posted with it, it's 2 directions away, but what would be the formula to do this? The problem arises since, like in the example, dir1 is 15, and dir2 is 1, so abs(dir2-dir1)=14.
If any of this makes sense, any advice?