How to get the number of subfolders within a subfolder within resources?

Hi, I have a subfolder called "Items" in my Resource folder. In this subfolder will be alot of folders named with the itemname, containing a txt file with properties of this items and a sprite as icon. I know this might not be the best way, but I am trying different stuff right now to find the best solution. But I already have a problem here. How do I get the number of subfolders in the Item folder?

I tried Resources.LoadAll("Items/").Length in all kind of different ways. But it always gives me the number of files within the subfolders, not the subfolders itself.

So, how can I do that?