 This format generates a total of 51 matches, compared with 31 matches for the previous 16-team tournament, to be played over a period of 31 days.UEFA's general secretary Gianni Infantino previously described the format as "not ideal" due to the need for third-ranked teams in the group stage advancing, leading to difficulty in preventing situations where teams might be able to know in advance what results they need to progress out of the group, leading to a lack of suspense for fans, or even the prospect of mutually beneficial collusion between teams.Each national team had to submit a squad of 23 players, three of whom must be goalkeepers, at least ten days before the opening match of the tournament.