Cricket is a multi-faceted sport with different formats, depending on the standard of play, the desired level of formality, and the time available. One of the main differences is between matches limited by time in which the teams have two innings apiece, and those limited by number of overs in which they have a single innings each. The former, known as first-class cricket if played at the senior level, has a scheduled duration of three to five days (there have been examples of "timeless" matches too); the latter, known as limited overs cricket because each team bowls a limit of typically 50 overs, has a planned duration of one day only. A separate form of limited overs is Twenty20, originally designed so that the whole game could be played in a single evening (3 hours), in which each team has an innings limited to twenty overs.