Task: Question Answering
Input (English): Passage: Most of Melodifestivalen's rules are dictated by those of the Eurovision Song Contest.  However, regulations have been introduced by the Swedish broadcasters. The competition's official rules are released by SVT early in preparation for each year's Melodifestival, to ensure any changes are noted by songwriters and performers.
There was a limit of six people on stage for each performance. This included the Melodifestivalen choir (huskören, literally "the house choir"), a five-person group of flexible backing singers used by most participants. Artists could use some or all of the back-up singers, or use their own group. All vocals had to be completely live; human voices were not allowed on backing tracks. However, from 2009, the number of performers allowed on stage was eight, and voices were allowed on backing tracks. A live orchestra was used every year from the event's debut to 2000, except 1985 and 1986. Two orchestras were used between 1960 and 1963, a large orchestra and Göte Wilhelmsons kvartett, a jazz quartet. Since 2001, participants have performed to backing tracks.
Entries cannot be publicly broadcast until the semi-finals are previewed on radio. Entries eliminated in the semi-finals may be broadcast as soon as the semi-final has finished. An embargo is placed on songs that qualify for the later rounds until the previews for the Second Chance are broadcast. After this, restrictions on the broadcast of contestant songs are lifted.Broadcasters sometimes make sweeping changes to winning songs before they go to Eurovision. For example, at Melodifestivalen 1961, Siw Malmkvist won with "April, April". Performing after her victory, she stumbled on the lyrics of the song and laughed out loud. The press criticised this as childish. SR replaced her with Lill-Babs for the Eurovision Song Contest. The 1987 winner "Fyra bugg och en Coca Cola", performed by Lotta Engberg, is another example; the song's title was changed to "Boogaloo" for Eurovision, as use of a brand name was against the Contest's rules. This name was chosen as Sweden's two previous Eurovision winners had also included the suffix "-loo".Until 1999, competing songs were only permitted in Swedish, apart from 1965, 1973, 1974, 1975. This did not stop most winning entries recording English (and other language) versions of their songs. Since the abolition of Eurovision's language restrictions in 1999, regardless of the performance language at Melodifestivalen, every Swedish entry has been in English. Spanish, French, Greek, Italian, Portuguese, Bosnian and Persian are among the other languages to have featured. Cameron Cartio's entry in Melodifestivalen 2005 was performed in a constructed language. 
Question: What is the full name of the vocalist who SR replaced with Lill-Babs?
Output (English): Siw Malmkvist.