Full version of cold jokes in mental hospital

Are you asking what the full version of this sentence is? I'm a psychopath, not a fool.

According to the inquiry group, the original text of this sentence is "I am mentally ill, not a fool." From a joke about mental illness.

The original story is funnier than April Fool's Day: he drove to a mental hospital to deliver something. Not long after the tire burst, he mended the tire there and accidentally dropped the screw on the tire. He was very upset and muttered to it. As a result, a mental patient passed by, looked at it and said, "Take your remaining tires, pull out a screw for each person, equip them, and then slowly drive to the city to find a shop to repair them." The man suddenly realized, "How can you be so smart? Why did you come to a mental hospital? " . The patient said, "I am mentally ill, not stupid."