Number of selections in HS dropbox

Please what is the best way to find out the number of selections in a drop-box programatically? The reason I need this is for a count.

I did a print and it seems it is just an array with all items sequentially. So if you have a HS selection with 3 levels and you chose 3 selections, you get nine items in the array. What I am after is to know if the number of selections (3 in this example) is stored anywhere. If not will need to deduce from Numer in array divided by HS depth of tree. Thanks