What is the fine-grained topic of the following text: The dismal odds of winning the Mega Millions jackpot — 1 in 302.5 million — mean there are 302.5 million potential number combinations, or a little less than one combination for each of the 328 million people living in the U.S. For last Friday's drawing, about 59 per cent of possible combinations were taken. Only return the topic.
Odds of winning the Mega Millions jackpot