The Sultan had 52 wise men to advise him, and each of these advisors, being exceedingly wise, had exactly one wife. One day, the Sultan found out that 13 of the advisors were cuckolds: their wives were cheating on them. How wise could his advisors be, if so many were ignorant of this? So he commanded his janissaries gather up all of the advisors and lead them into the great hall. There, the Grand Vizier told them that they would all be thrown into prison, and executed in one year.
Each advisor had one last chance to be with his wife, under close watch by the janissaries. The wives, wiser than their husbands, all knew very well who were the cuckolds. During the last visit, each wife told her husband the names of all of the other advisors who were cuckolds. Of course, no wife who was cheating told her own husband! Other than that, no advisor was allowed to speak to anyone, and was lead immediately to solitary confinement.
Their only hope of escaping death was the following: Each morning the Grand Vizier would visit each of the advisors, and ask whether that man was a cuckold. Each advisor could remain silent, or answer yes or no. If any advisor answered incorrectly, then all of the advisors would be immediately tortured and executed. Otherwise, if there came a day that each cuckold answered yes, then all the advisors would all be freed, restored to their positions, and made wealthy beyond their dreams.
What strategy could each advisor follow that would allow all of them to escape their doom?