Powershell Variable trimming

Geeks,

Im trying to trim the below string but unable to get what i acheive-

$string = "\\winfile01\D$\share01\2016\May\Dept"

I would like the $string to be trimmed and saved as value "Dept" stored in variable.

i already tried the various trim functions, but not able to get what i want.

Let me know how to proceed with it.

Cheers, Alan.