Here is the scenerio:

A1 contains the workschedule
B1 contains a specific day
C1 I want to add 2 days on to B1, but the days fust be contained in A1

Example

A1: MTRS9a-10p (m=monday t=tuesday, r=thursday, s=saturday)
B1: R
C1: I would want 2 working day from this day. So, I would want it to
show M

Example 2:
A1: MTRS9a-10p
B1: M
C1: I want to display R

Any Ideas? I am totally stumped. I thought of doing match/index/
vlookups.
Any help would be GREATLY appreciated =)