The National Football League (NFL) is a professional American football league consisting of 32 teams, divided equally between the National Football Conference (NFC) and the American Football Conference (AFC). The NFL is one of the four major North American professional sports leagues, the highest professional level of American football in the world, the wealthiest professional sport league by revenue, and the sport league with the most valuable teams. The NFL’s 17-week regular season runs from early September to late December, with each team playing 16 games and having one bye week. Following the conclusion of the regular season, seven teams from each conference (four division winners and three wild card teams) advance to the playoffs, a single-elimination tournament culminating in the Super Bowl, which is usually held on the first Sunday in February and is played between the champions of the NFC and AFC. Green Bay Packers are the most successful team with 13 titles. Kansas City Chiefs are the defending champions.