Rules for staff scheduling

Staff must not work too many consecutive shifts.

Staff cannot work back to back shifts.

Staff cannot be off for too many consecutive shifts.

One supervising nurse must be present for each ward at all times.  That 
supervising nurse must have the specialty of that particular ward.

During the day, each ward must have 5 regular nurses of which at least 3 
must have the specialty of that ward.  As well, 2 doctors of that specialty
must be present.

During the night each ward must have 2 regular nurses of which at least one
must have that ward's specialty.  As well, 1 doctor of that specialty must
be present as well.

Staff cannot be scheduled to work ward and perform surgery at the same time.

Operations must have 2 doctors and 2 nurses with the appropriate specialty 
present.