You are in a country where there are only liars and truth-tellers, and they cannot be told apart by sight. you set out on a dangerous trip, because there is a fork in the road that can lead either to a crocodile swamp or to safety. when you reach the fork, the signpost is gone, but there are two people standing there. you know that they will answer only one question between them. what question can you ask either of them that will tell you which road is safe? (you only get one question.