Question: How many acts were in the opera in which "Donna non vidi mai" was in?

Context paragraphs:
The Great Escape (festival): The Great Escape was a music festival held at Newington Armory, located within Sydney Olympic Park that took place in 2006 and 2007.  Initially held over the Easter long weekend for the first two events, in 2008 it was announced the festival would take place on the Labour Day weekend, however the event was cancelled 2 months from the date due to poor ticket sales .  It evolved from the 2005 Cockatoo Island Music Festival.  The music and other attractions run over three full days (Good Friday to Easter Sunday in 2006–07), with some patrons camping from Thursday evening to Monday morning.  Punters could attend either for the full weekend camping, purchase a 3-day pass and commute each day or attend a single day.  Many acts also played the East Coast Blues & Roots Music Festival the same weekend, however The Great Escape line-up is more diverse featuring pop, hip hop, electronic and rock acts that would not fit into a Blues and Roots line-up.  In addition to musical acts, there is also a wide range of other features such as comedy acts, bingo and trivia, conspiracy theory talks and yoga.  There is no immediate future for the Great Escape at this point, but organisers are confident it will be resurrected in the near future.

Steve Thompson (songwriter): Steve Thompson (born 24 April 1952) is a British songwriter and record producer who is responsible for a number of single and album chart hits and well known songs recorded by international recording artists.  He was instrumental in setting up the influential Neat Records.  He was particularly active as a producer during (as well as being partially responsible for), the NWOBHM years (New Wave of British Heavy Metal) During this time he produced many acts and kick-started the careers of several influential heavy metal acts including the first recordings of Newcastle band Venom ( who are widely credited with the invention of black metal) and Raven who have been credited with being hugely influential by Metallica.

Pairat Decharin: Dr. Pairat Decharin (Thai: ไพรัตน์ เดชะรินทร์ ; rtgs: "Phairat Decharin" , died 26 May 1991) was the governor of Chiang Mai Province, Thailand.  He died in the crash of Lauda Air Flight 004 on 26 May 1991, with his wife.  Charles S. Ahlgren, the former U.S. consul general to Chiang Mai, said "That accident not only took their lives and that of many of Chiang Mai's leaders, but dealt a blow to many development and planning activities in the town."

Donna non vidi mai: Donna non vidi mai ("English": I have never seen a woman) is an aria from the first act of Giacomo Puccini's opera, "Manon Lescaut".

Veni Vidi Theatre Company: The Veni Vidi Theatre Company is an independent theatre company based in London.  The company specialises in producing site specific pieces of theatre and creating theatrical performances for unusual or non established performance areas.  Their work varies from adaptations of Classical texts to more New Writing works.  The company is committed to exploring the limitless possibilities of creating innovative and diverse work within the theatrical art form in parts of London that aren’t consider theatrical spaces.  The original company name being taken from a famous Latin saying Veni Vidi Vici, reportedly written by Empire Julius Caesar, meaning ‘I Came, I Saw, I Conquered’.

Budgie (band): Budgie are a Welsh hard rock band from Cardiff.  They are described by author Garry Sharpe-Young as one of the earliest heavy metal bands and a seminal influence to many acts of that scene, with fast, heavy rock (an influence on the new wave of British heavy metal (NWOBHM) and acts such as Metallica) being played as early as 1971.  The band has been noted as "among the heaviest metal of its day".

Manon Lescaut (Puccini): Manon Lescaut is an opera in four acts by Giacomo Puccini, composed between 1890 and 1893.  The story is based on the 1731 novel "L'histoire du chevalier des Grieux et de Manon Lescaut" by the Abbé Prévost and should not be confused with "Manon", an 1884 opera by Jules Massenet based on the same novel.

Bay City Rollers: The Bay City Rollers are a Scottish pop band whose popularity was highest in the mid 1970s.  The "British Hit Singles & Albums" noted they were "tartan teen sensations from Edinburgh", and were "the first of many acts heralded as the 'biggest group since the Beatles' and one of the most screamed-at teeny-bopper acts of the 1970s".  For a relatively brief, but fervent period (nicknamed "Rollermania"), they were worldwide teen idols.  The group's line-up had numerous changes over the years, but the classic line-up during its heyday included; guitarists Eric Faulkner and Stuart John Wood, singer Les McKeown, bassist Alan Longmuir, and drummer Derek Longmuir.

Quidi Vidi: Quidi Vidi (pronunciations vary, even amongst longtime residents, but "Kiddy Viddy" is the most common) is a neighbourhood in St. John's, Newfoundland and Labrador.  The neighbourhood is named for both Quidi Vidi Lake (where the Royal St. John's Regatta is held the first Wednesday in August, weather permitting) and Quidi Vidi Harbour - known locally as "The Gut".  Located in Quidi Vidi is the Quidi Vidi Battery Provincial Historic Site, which had significance as a battery during the War of 1812.  The village is also home to Newfoundland's largest microbrewery, the Quidi Vidi Brewing Company.  It has many different types of plants and animals.  There are numerous scenic places to visit.

Pleasantville Music Festival: The Pleasantville Music Festival is a single-day music festival which takes place annually at Parkway Field in Pleasantville, New York.  Some of the many acts that have performed at the Pleasantville Music Festival are: Guster, Gin Blossoms, Jakob Dylan, Joan Osborne, Marc Cohn, Big Head Todd & the Monsters, the English Beat, and Roger McGuinn.  These major acts perform alongside up and coming national acts and small local bands from around the tri-state area.

Supporting paragraphs: Donna non vidi mai Manon Lescaut (Puccini)
Answer: four