Question: In what state did Olivia Newton-John perform Summer Nights? 

full_context: Document 1: Caesars Entertainment Corporation: Caesars Entertainment Corporation, is an American gaming corporation based in Paradise, Nevada that owns and operates over 50 casinos and hotels, and seven golf courses under several brands. It is the fourth-largest gaming company in the world, with annual revenues of $8.6 billion (2013). Caesars is a public company, majority-owned by a group of private equity firms led by Apollo Global Management and TPG Capital.
Document 2: Lady Gaga Live at Roseland Ballroom: Lady Gaga Live at Roseland Ballroom was the first residency show by American singer Lady Gaga. Performed at the Roseland Ballroom in Manhattan, New York, the residency show began on March 28 and concluded on April 7, 2014, after completing seven shows. It was the final event hosted by the venue after it was announced that it was being closed down and being replaced with a 42-story skyscraper. Gaga revealed that Roseland was the only venue in New York City that she had never played, although she had visited there previously to watch shows. A poster announcing the event was released, showing an old image of Gaga taken before the time she became successful as a recording artist.
Document 3: A Summer Night with Olivia Newton-John: A Summer Night with Olivia Newton-John was the eighteenth concert tour by Australian singer Olivia Newton-John, in support of her sixth soundtrack "A Few Best Men". The tour name drifts from her 1978 hit, "Summer Nights", from the musical film "Grease". It is Newton-John largest tour since the Heartstrings World Tour, which runs from 2002 to 2005. It was her first tour in the United Kingdom in over 30 years.
Document 4: Number 1 to Infinity (residency show): Carey announced the residency show during her pre-recorded interview on "The Ellen DeGeneres Show". The announcement follows reports that Canadian singer Celine Dion would not be returning to the venue who postponed her shows so that she could continue to take care of her ill husband. Later that spring 2015 Celine announced that she will return to Caesars Palace on August 27, 2015. Speaking of the residency, Carey said "I'm going to do my first ever residency in Vegas at Caesars. This is a special event for me. And again, I have to hope that the fans will enjoy this cause I'm gonna be performing, which was kind of inspired by my album "#1's", and this is now the updated version with eighteen of them. Hopefully other people will enjoy this. I've never done this before." Tickets went on sale January 15, 2015.
Document 5: Excalibur Hotel and Casino: Excalibur Hotel and Casino is a hotel and casino located on the Las Vegas Strip in Paradise, Nevada, in the United States. It is owned and operated by MGM Resorts International.
Document 6: Flamingo Las Vegas: Flamingo Las Vegas (formerly The Fabulous Flamingo and Flamingo Hilton Las Vegas) is a hotel and casino located on the Las Vegas Strip in Paradise, Nevada. It is owned and operated by Caesars Entertainment Corporation.
Document 7: A New Day...: A New Day... was a Las Vegas residency show performed by Canadian singer Celine Dion at the 4,000-seat Colosseum at Caesars Palace in Las Vegas. It was created and directed by Franco Dragone (known for his work with Cirque du Soleil) and premiered on 25 March 2003. 90-minute event, "A New Day..." introduced a new form of theatrical entertainment, a fusion of song, performance art, innovative stage craft and state-of-the-art technology. Dion was originally contracted for three years (Dion received about $100 million, plus 50 percent of the profits during the three-year contract), however, due to its immediate success, the show continued for an additional two years. "A New Day..." ended on 15 December 2007, after a 5-year run of more than 700 shows and 3 million spectators. It reached one of the highest concert grosses in music history, grossing over $400,000,000 in its entire run.
Document 8: Planet Hollywood Las Vegas: Planet Hollywood Las Vegas (formerly Tally-Ho, King's Crown and Aladdin) is a hotel and casino located on the Las Vegas Strip in Paradise, Nevada. It is owned and operated by Caesars Entertainment Corporation.
Document 9: Caesars Palace: Caesars Palace is a AAA Four Diamond luxury hotel and casino in Paradise, Nevada, United States. The hotel is situated on the west side of the Las Vegas Strip between Bellagio and The Mirage. It is one of the most prestigious casino hotels in the world and one of Las Vegas's largest and best known landmarks.
Document 10: Paris Las Vegas: Paris Las Vegas is a hotel and casino located on the Las Vegas Strip in Paradise, Nevada. It is owned and operated by Caesars Entertainment Corporation.
Document 11: Jennifer Lopez: All I Have: Jennifer Lopez: All I Have is the first residency show by American entertainer Jennifer Lopez. Performed at The AXIS auditorium located in the Planet Hollywood Resort & Casino in Las Vegas, Nevada, the residency show began on January 20, 2016.
Document 12: Summer Nights (residency show): Summer Nights is the debut residency show by Australian recording artist, Olivia Newton-John. The show takes place in the Donny & Marie Showroom, at the Flamingo Las Vegas. The show began April 2014 and is slated to complete September 2015.
Document 13: Flamingo &amp; Caesars Palace station: Flamingo & Caesars Palace station is a station on the Las Vegas Monorail. The station is an island platform located on the Flamingo side of Las Vegas Boulevard, 2000 feet (610 m) from Caesars Palace.
Document 14: Live at the Sydney Opera House: Olivia Newton-John and the Sydney Symphony Orchestra: Live at the Sydney Opera House is a HD video (16:9) released in 2008 for a tour of four concerts at the Sydney Opera House of singer Olivia Newton-John. The show was done in March 2006 with her band and Sydney Symphony conducted by Rick King. Produced by Olivia's Gaia Productions.
Document 15: Britney: Piece of Me: Britney: Piece of Me is the first residency show by American singer Britney Spears, performed at The AXIS auditorium located in the Planet Hollywood Resort & Casino in Las Vegas, Nevada. The show had its opening night on December 27, 2013. In 2015, Spears extended her contract with Planet Hollywood through 2017.
ground_truth: Nevada