Hi Aron,
Thanks for your reply.

The answers for your reply are as follows:
1.Will there always be either one or two digits after a letter in the end?
A.Yes

2.Will there always be a capital M there?
A. Yes

Could these values be of a different length than 9 or 10 characters?
A. No

If there only is one digit, is 9 one less than 0?
A. I dont understand this question.
There can be M1 to M8 ,M11 to M18, M91 to M98

Thanks in advance for a solution.