Geocache, MD5, some parts of password known some parts not

Hi,
I´m doing geocaching.
now i have a cache where the coordinates are encryptet in plain MD5

i know that the coordinates are in this format:
N.xx.yy.zzz
E.aa.bb.ccc

The Upper case Letters are given and the dots are given,
so i neet a rule or something that usses the given characters and counts the lowercase letters numeric

i´m using hashcat GUI

hope you understand what i´m thinking of....