In seasons ten and eleven, a further round was added in Las Vegas, where the contestants perform in groups based on a theme, followed by one final solo round to determine the semi-finalists. At the end of this stage of the competition, 24 to 36 contestants are selected to move on to the semi-final stage. In season twelve the Las Vegas round became a Sudden Death round, where the judges had to choose five guys and five girls each night (four nights) to make the top twenty. In season thirteen, a new round called "Hollywood or Home" was added, where if the judges were uncertain about some contestants, those contestants were required to perform soon after landing in Los Angeles, and those who failed to impress were sent back home before they reached Hollywood.