A certain retailer promotes merchandise by using the following policy: At all times there is either a manager' s sale or a holiday sale or both going on  All sales are run for exactly one calendar month  In any given month, if a manager wishes to clear out a particular line of merchandise, then a manager' s sale is declared  If a holiday falls within the calendar month and there is excess merchandise in the warehouse, then a holiday sale is declared
However, there is no holiday that falls within the month of August and, in that month, the warehouse never contains excess merchandise
If a manager's sale is being run in some month, then there is no excess merchandise in the warehouse in that month.