A cruise line is scheduling seven week-long voyages for the ship Freedom. Each voyage will occur in exactly one of the first seven weeks of the season: weeks 1 through 7. Each voyage will be to exactly one of four destinations: Guadeloupe, Jamaica, Martinique, or Trinidad. Each destination will be scheduled for at least one of the weeks. The following conditions apply to Freedom’s schedule:
          Jamaica will not be its destination in week 4.
          Trinidad will be its destination in week 7.
          Freedom will make exactly two voyages to Martinique, and at
                least one voyage to Guadeloupe will occur in some week
                between those two voyages.
          Guadeloupe will be its destination in the week preceding any
                voyage it makes to Jamaica.
          No destination will be scheduled for consecutive weeks.