Question: The American singer-songwriter Taylor Swift released which album co-written by Max Martin and Shellback and inspired by the singer's "semi-toxic" relationships she experienced?

Context paragraphs:
1989 (Taylor Swift album): 1989 is the fifth studio album by American singer-songwriter Taylor Swift released on October 27, 2014, through Big Machine Records.  Swift began composing the album following release of previous studio effort, "Red" (2012).  Over the course of the two-year songwriting period, she collaborated with producers Max Martin and Shellback—Martin served as the album's executive producer alongside Swift.  The album's title was named after the singer's birth year and inspired by the pop music of the 1980s.

Bad Blood (Taylor Swift song): "Bad Blood" is a song by American singer-songwriter Taylor Swift, from her fifth studio album "1989" (2014).  The remixed version of the song, featuring American rapper Kendrick Lamar, was released on May 17, 2015, by Republic Records as "1989"' s fourth single.  The album version was written by Swift, Max Martin, and Shellback, with Lamar writing his verses on the remixed version.  The lyrics of "Bad Blood" describe betrayal by a close friend.  The album version is the eighth track of "1989".

Shake It Off: "Shake It Off" is a song recorded by American singer-songwriter Taylor Swift from her fifth album, "1989" (2014).  Written by Swift, Max Martin and Shellback, it is an uptempo dance-pop track considered to be a departure from Swift's earlier country pop music style.  "Shake It Off" is the sixth track on the album and serves as the lead single.  The song premiered during a Yahoo! live stream session on August 18, 2014 (also streaming internationally online); its music video was also released the same day.  Several hours later, the song was made available for digital download.

Wildest Dreams (Taylor Swift song): "Wildest Dreams" is a song recorded by American singer-songwriter Taylor Swift for her fifth studio album, "1989".  The song was released to radio by Big Machine Records on August 31, 2015, as the album's fifth single.  Swift co-wrote the song with its producers Max Martin and Shellback.  Musically, "Wildest Dreams" is a love ballad with a prominent dream pop influence, with the lyrics describing Swift's plea for her lover to remember her.

Blank Space: "Blank Space" is a song by American singer-songwriter Taylor Swift from her fifth studio album "1989" (2014).  It was written by Swift, Max Martin and Shellback.  The song was released to the radio by Republic Records on November 10, 2014 as the album's second single, after "Shake It Off" and is the second track on the album.  Musically, "Blank Space" is an electropop song with lyrics that satirize the media's perception of Swift and her relationships.

Style (Taylor Swift song): "Style" is a song by American singer-songwriter Taylor Swift and is the third track from her fifth album, "1989" (2014).  The song was written by Taylor Swift, Max Martin, Shellback, and Ali Payami.  It was released to radio by Republic Records, in partnership with Swift's label Big Machine Records, on February 9, 2015, as the album's third single, following "Blank Space".

Red (Taylor Swift album): Red is the fourth studio album by American singer-songwriter Taylor Swift.  It was released on October 22, 2012, by Big Machine Records, as the follow-up to her third studio album, "Speak Now".  The album title was inspired by the "semi-toxic relationships" that Swift experienced during the process of conceiving this album, which Swift described the emotions she felt as "red emotions" due to their intense and tumultuous nature.  "Red" touches on Swift's signature themes of love and heartbreak, however, from a more mature perspective while exploring other themes such as fame and the pressure of being in the limelight.  The album features collaborations with producers and guest artists such as Gary Lightbody of Snow Patrol and Ed Sheeran and is noted for Swift's experimentation with new musical genres.  Swift completed The Red Tour in support of the album on June 12, 2014, which became the highest-grossing tour of all time by a country artist, grossing over $150 million.

Taylor Swift (album): Taylor Swift is the debut studio album by American singer-songwriter Taylor Swift, released on October 24, 2006, by Big Machine Records.  Swift was 16 years old at the time of the album's release and wrote its songs during her freshman year of high school.  Swift has writing credits on all of the album's songs, including those co-written with Liz Rose.  Swift experimented with several producers, ultimately choosing Nathan Chapman, who had produced her demo album.  Musically, the album is country music styled, and lyrically it speaks of romantic relationships, a couple of which Swift wrote from observing relationships before being in one.  Lyrics also touch on Swift's personal struggles in high school.

We Are Never Ever Getting Back Together: "We Are Never Ever Getting Back Together" is a song recorded by American singer-songwriter Taylor Swift for her fourth studio album, "Red" (2012).  Swift co-wrote the song with its producers, Max Martin and Shellback.  The song was released as the lead single from "Red" on August 13, 2012, by Big Machine Records.  Its lyrics depict Swift's frustrations at an ex-lover who wants to re-kindle their relationship. " Rolling Stone" magazine named the song the second best song of 2012 while it took the fourth spot in "Time"' s end-of-year poll.  It has received a Grammy Award nomination for Record of the Year.  It also received a People's Choice Awards nomination for Favorite Song of the Year.

I Knew You Were Trouble: "I Knew You Were Trouble" is a song recorded by American singer-songwriter Taylor Swift for her fourth studio album, "Red" (2012).  It was released on October 9, 2012, in the United States by Big Machine Records as the third promotional single from the album.  Later, "I Knew You Were Trouble" was released as the third single from "Red" on November 27, 2012, in the United States.  It was written by Swift, Max Martin and Shellback, with the production handled by the latter two.

Supporting paragraphs: We Are Never Ever Getting Back Together Red (Taylor Swift album)
Answer: Red