具体描述
Mr. Birthday is very good at organizing birthday parties. He likes to make sure that everyone he knows has a party on his or her birthday. But there seems to be an important birthday coming up that Mr. Birthday knows nothing about . . .
Mr. Birthday is very good at organizing birthday parties. He likes to make sure that everyone he knows has a party on his or her birthday. But there seems to be an important birthday coming up that Mr. Birthday knows nothing about . . .
