One day, a penguin walked into a restaurant and took a seat. He said to the waiter, I would like your most special ice cream. The waiter nodded and went to the kitchen.Soon, the waiter returned with a splendid ice cream, and the penguin excitedly ate it. After finishing, the penguin took out his wallet and discovered that he had forgotten to bring his money. Embarrassed, the penguin said to the waiter, Oh, I'm really sorry, I forgot to bring my money. Is there another way I can pay?The waiter looked at the penguin and laughed, Of course, you can help us wipe some tables.The penguin happily agreed, and the waiter added, But remember to bring your money next time because we don't accept ice coins.