Task: Question Answering
Input (English): Passage: The seventh and eighth major Nine Inch Nails studio-releases, Ghosts I–IV and The Slip, were released in March and May 2008 respectively. Both albums feature contributions from live-band member Alessandro Cortini.  Since the release of Ghosts I–IV, a 25-date tour was announced in several North American cities.  Cortini and Freese returned as members from the previous tour, while Robin Finck rejoined the band.  The lineup was initially to include Rich Fownes, but before any scheduled performances it was revealed that Justin Meldal-Johnsen would instead be contributing on bass guitar.
Supporting acts for the tour include Deerhunter, Crystal Castles, Does It Offend You, Yeah?, Ghostland Observatory, A Place to Bury Strangers, and White Williams. In early June, a tour EP was released for free on the Nine Inch Nails website featuring four songs from the supporting artists and one from Nine Inch Nails.  The files are DRM-free MP3s that are fully tagged, and included with the download are desktop wallpapers and a printable tour poster.
The band headlined the 2008 Lollapalooza festival, the 2008 Virgin Festival, and the first Pemberton Music Festival.
In May 2008, Nine Inch Nails announced that premium seating for all the upcoming 2008 tour shows would be offered in a pre-sale for fans who registered at the official Nine Inch Nails website. In an effort to combat ticket scalpers, each concert ticket will list the purchaser's legal name.  The ticketing process was previously used for smaller pre-sales and was available exclusively to fan club members.
On July 26, Reznor introduced an "unplugged" portion into the live show in which the band steps to the front of the stage about an hour into the show, with Reznor on vibraphone and bassist Meldal-Johnsen playing an upright bass. The 20-minute jazzy, acoustic set is taken mostly from Ghosts I - IV.  The stage show also featured mesh LED curtains that projected various visuals, ranging from falling rain to static to a ruined city, and made the band appear to be playing on "a stage that appeared to be constructed entirely out of lights." Nine Inch Nails later confirmed that the tour was to extend to South America  and it was thought this would be the last Americas set of dates but soon after Reznor announced yet more North American dates including two dates in tourist capital Florida.
On October 8, 2008, after finishing up their last show in South America, Reznor posted on the official Nine Inch Nails website blog that Josh Freese would be leaving the band following the completion of the current tour. Shortly after, it was announced that Alessandro Cortini would also be leaving the band. On November 15, 2008, Reznor announced via the official Nine Inch Nails website that Ilan Rubin of Lostprophets would be replacing Freese after his departure at the end of 2008. No replacement was announced for Cortini, and the band subsequently toured as a 4-piece without a full-time keyboard player. 
Question: In what month was Ghosts I-IV released?
Output (English): March.