The marriage was concluded between a young man and a young woman, and they agreed to finalize the marriage after three years. However, as the date approached, the young woman withdrew. Her guardian returned all the dowry to the young man and added twenty thousand yuan; this is because they had agreed in the contract that if either party withdrew, they would have to pay an additional twenty thousand as a penalty for breaching the contract. Is it permissible for the young man to take this money?