The Campeonato Brasileiro Série A, commonly referred to as Campeonato Brasileiro and popularly as Brasileirão, is a Brazilian professional league for men's football clubs. At the top of the Brazilian football league system, it is the country's primary football competition. Contested by 20 clubs, it operates on a system of promotion and relegation with the Campeonato Brasileiro Série B. It is currently sponsored by Chevrolet and thus officially known as the Brasileirão Chevrolet.