Formula One, abbreviated to F1, is the highest class of open-wheeled auto racing series managed by the Fédération Internationale de l'Automobile (FIA), motorsport's world governing body. The "formula" in the name alludes to a series of FIA rules to which all participants and vehicles are required to conform. The Formula One World Championship season consists of a series of races around the world, known as Grands Prix, usually held on purpose-built circuits, and in a few cases on closed city streets. Each Grand Prix meeting lasts three days with either one or three practice sessions before a three-part qualifying session on Saturday to set the starting order for Sunday's race. A Saturday sprint is held at select events, with the starting grid determined by a separate, shorter qualifying session held on Friday. Grands Prix are frequently named after the country, region or city in which they are raced, and in some seasons, nations have hosted more than one event. Should Formula One hold two or more races in the same nation in the same year, on either a different or the same track, then their names will be different. The results of each Grand Prix held throughout the season are combined to decide two annual championships, one for drivers and one for constructors.