The tournament teams include champions from 32 Division I conferences (which receive automatic bids), and 36 teams which are awarded at-large berths. These "at-large" teams are chosen by an NCAA selection committee, then announced in a nationally televised event on the Sunday preceding the "First Four" play-in games, currently held in Dayton, Ohio, and dubbed Selection Sunday. The 68 teams are divided into four regions and organized into a single-elimination "bracket", which pre-determines, when a team wins a game, which team it will face next. Each team is "seeded", or ranked, within its region from 1 to 16. After the First Four, the tournament occurs during the course of three weekends, at pre-selected neutral sites across the United States. Teams, seeded by rank, proceed through a single-game elimination bracket beginning with a "first four" consisting of 8 low-seeded teams playing in 4 games for a position in the first round the Tuesday and Wednesday before the first round begins, a first round consisting of 64 teams playing in 32 games over the course of a week, the "Sweet Sixteen" and "Elite Eight" rounds the next week and weekend, respectively, and – for the last weekend of the tournament – the "Final Four" round. The Final Four is usually played during the first weekend of April. These four teams, one from each region (East, South, Midwest, and West), compete in a preselected location for the national championship.