Passage: "Shake It Off" is a song recorded by American singer-songwriter Taylor Swift from her fifth album, 1989 (2014). Swift co-wrote the song with its producers 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.

Question: Who co-wrote the song "Shake It Off" with Max Martin and Shellback?
Taylor Swift