A third thing that tends to “fall in the fall” is people’s amount of physical activity. It is believed that people generally gain weight in the colder months in large part due to this lack of physical activity. Lou decided to be pro-active about this and promised himself he would exercise at least four days of every calendar week (or every Sunday through Saturday time period). If Lou never wants to skip exercising on consecutive days within a calendar week, and he exercises exactly four days out of the seven, how many different workout schedules are possible for a calendar week?