You run the emergency department of a local hospital. There are 30 doctorsin your staff and they all work 5 days a week. They would all like to get 2 consecutive days off a week, but the needs of your department make that difficult to achieve. You need a total of 28 doctors on Saturdays, 18 doctors on Sundays and Mondays, 25 doctors on Tuesdays and Wednesdays, 15 doctors on Thursdays and 21 doctors on Fridays. Find a schedule that minimizes the number of doctors taking non-consecutive days off. How many doctors have non-consecutive days off in your optimal schedule?