Once upon a time there was a prince who was determined to marry a real princess, but he didn't know what a real princess was like, so he asked a witch for advice. The witch suggested that there are three criteria to judge the real princess. First, she is polite to everyone; Second, she pays attention to the love for the rich and the poor. Third, her skin must be very sensitive.
How to test very sensitive skin?
Put a pea under the mattress on the twentieth floor. If a real princess sleeps in a bed, she can feel peas!
According to these standards, the prince met many princesses, but none of them passed the three tests, especially many failed the pea test. The final result is that a maid passed three tests. The maid accidentally slept in the tested bed for one night, but she couldn't sleep well because of the existence of peas. Finally, the prince and the girl got married and they lived happily ever after.
This story is adapted from Andersen's fairy tale princess and the pea. As a result, a princess finally passed the test, but the adapted version above is obviously changed to cater to modern concepts.