Question: What number of studio album release did U2's Innocence + Experience Tour support?
Context: Songs of Experience is the upcoming fourteenth studio album by Irish rock band U2.  It will be released on 1 December 2017.  The album is intended to be a companion piece to U2's previous record, "Songs of Innocence" (2014).  Whereas its predecessor explored the group members' adolescence in Ireland in the 1970s, "Songs of Experience" thematically will be a collection of letters written by lead vocalist Bono to people and places closest to his heart.  The personal nature of the lyrics reflects a "brush with mortality" that he had during the album's recording.  The band collaborated with a variety of producers for the record, including Steve Lillywhite, Ryan Tedder, Jacknife Lee, Jolyon Thomas, and Andy Barlow. The FanMail Tour is the debut headlining tour by American group TLC.  The tour support their third studio album, "FanMail".  The tour visited North America with dates planned in Japan and Europe.  However, the international dates after the second North American leg were cancelled. Songs of Innocence is the thirteenth studio album by Irish rock band U2.  Released on 9 September 2014, it was produced by Danger Mouse, with additional production from Paul Epworth, Ryan Tedder, Declan Gaffney, and Flood.  The album was announced at an Apple Inc. product launch event and released the same day to all iTunes Store customers at no cost.  It was exclusive to iTunes, iTunes Radio, and Beats Music until 13 October 2014, when it received a physical release on Island and Interscope Records.  The digital release made the record available to over 500 million iTunes customers, for what Apple CEO Tim Cook marketed as "the largest album release of all time". Innocence + Experience: Live in Paris (stylised as iNNOCENCE + eXPERIENCE: Live in Paris) is a 2016 concert film by Irish rock band U2.  It was shot on 7 December 2015 at AccorHotels Arena in Paris, France, during the final date of the band's Innocence + Experience Tour.  The concert aired on American television network HBO the same day as the show, and was later released worldwide on home video on DVD, Blu-ray, and via digital download on 10 June 2016. To The Metal!  is the tenth full-length studio album by Gamma Ray.  It was released on 29 January 2010.  To promote the album, the band did a tour with Freedom Call and Secret Sphere.  The album was recorded in Kai's own studio in Hamburg in autumn 2009.  The band has recorded 12 songs.  Ten of them were featured on the regular album release, while the other two were bonus tracks appearing on the different editions of the album.  The band described some of the songs on the official website, revealing that there would be a full-throttle number called "Rise", a rhythmic and melodically diverse song called "Time To Live", and a multilayered anthem titled "All you need to know", featuring ex-Helloween frontman Michael Kiske.  Other songs mentioned are "No Need to Cry", a song written by Dirk Schlächter about the death of his father, "To The Metal", a song they played on various festivals before the album release and the atmospheric and dense "Empathy".  It is the last album featuring drummer Dan Zimmermann. The Innocence + Experience Tour (styled as iNNOCENCE + eXPERIENCE Tour) was a worldwide concert tour by rock band U2.  Staged in support of the band's 2014 album "Songs of Innocence", the tour visited arenas throughout 2015.  It was U2's first time playing arenas since 2005–2006 on their Vertigo Tour.  Comprising two legs and 76 concerts, the Innocence + Experience Tour began on 14 May 2015 in Vancouver, Canada.  It visited North America from May through July, and Europe from September through December.  Shows were predominantly booked in pairs for each market. The Queen of Hardships (sometimes credited as Queen of Hardships) is the 13th studio album by cantopop singer Prudence Liew.  This album marks the first Cantonese language studio album release from Liew in 15 years since her 1994 release of "夜有所思，日有所夢 Thoughts in the Night, Dreams During the Day" and the first studio album release in 9 years.  Her previous studio album was the mandopop album, "愛自己 Love Yourself" released in Taiwan in 2000. The Lovers Rock Tour is the fifth concert tour by British band Sade.  Predominately visiting amphitheaters in North America, the tour support the band's fifth studio album, "Lovers Rock".  Deemed by many critics as a comeback tour, it marks the band's first performances since 1994 and last until 2011.  Although many believed the trek would expand to other countries, this did not come to fruition.  With over 40 shows, it became the 13th biggest tour in North America, earning over 26 million. Wild About Nothing is debut studio album by Helen Hoffner.  It was the culmination of ten years work that started in 1982 when Helen joined the band The Astronauts (Stiff Records) with Simon Burton and David Lief.  Subsequently, Simon and Helen formed an all-girl band called The Marines (CBS/Sony Records) with Denny Jones and Sarah Pritchard; Simon wrote and produced the material and they were managed by Colin Lester.  After a couple of minor hit singles and tour support for Kylie Minogue in 1989, it was decided that Helen should become a solo artist.  For the next 18 months, Helen and Simon worked on putting her solo album together.  They signed to Warner Brothers and began recording in April 1992.  Produced by Hugh Padgham and Simon Burton, the album featured Vinnie Colaiuta - Drums; Pino Palidino - Bass; Dominic Miller - Guitar; Bob Marlett and Michael Scherchen - Keyboards.  The original pressing of the album only had 11 tracks; "Edge of a Dream" (featuring Bryan Adams) was added later on, not having been a part of the original album recording.  "Summer of Love", which was a hit in Norway and Finland, has been covered by Faye Wong and numerous other artists.  The album sold gold in Finland. The Ride the Lightning Tour was the second concert tour by American thrash metal band Metallica.  The tour was in support of Metallica's second studio album "Ride the Lightning".  Tank provided tour support in Europe, with WASP and Armored Saint supporting in North America.  Metallica performed for the first time at Monsters of Rock in front of 70,000 people.
Answer: thirteenth