Who can help me recall this joke? It is urgent. As detailed as possible, reward!

Here's the thing:

Mental hospital. One day, the dean invited all the mental patients to the spirit square and said, "I decided to choose the building director on the first, second and third floors, so please cooperate actively!" " So he took out a banana and said, "What is this?" "One man said," Bananas. " The dean said, "Congratulations, you are the person in charge on the first floor!" " He took out another rose and said, "What is this?" A lovelorn man said, "This is a rose!" The dean said, "You are the director on the second floor! "Take out another fruit and guess what it is (no matter how you answer, you are the director of the third floor of a mental hospital, which also means you are a mental patient [-]). Is there such a similar story?