There is a humorous joke.

An unknown man came to the toilet and squatted at the door. What should I do if I find no paper after defecation? He saw a water pipe in front of the door and thought, handle it with your hands and wash your hands. He wiped off the dirt with his right hand and turned on the tap with his left hand, but there was no water in the pipe at all. He became angry from embarrassment and slapped the tap hard with his right hand. The water didn't come out, but the severe pain made him put his hand into his mouth. It's the right hand