Because there are so many AKB48 members, they don't perform all at the same time. Instead, AKB48 consists of 5 teams called "Team A", "Team K", "Team B", "Team 4", and "Team 8". Most of the group's members are in one of these teams. Each team holds individual performances at the AKB theatre. These performances are a unique set list of around 15 to 20 songs, known as "stages". Each team has more than 20 members. For members who do not have enough experience to join a team, they are part of a group of "research students". The research students can take the place of a team member during performances if she is sick or unable to perform. When they are thought to have enough experience, they can join a team. 