"Hot n Cold" is a song by American singer Katy Perry. The song was written and composed by Dr. Luke, Max Martin, and Perry for her major mainstream debut album, One of the Boys. The track was released as the album's third single. Its chorus features a series of binary opposites (such as hot/cold, yes/no, in/out, up/down, wrong/right, black/white) to emphasize the unstable nature of the characters' relationship. It reached number three on the Billboard Hot 100, making it Perry's second consecutive top three single, after her previous worldwide hit "I Kissed a Girl". The single has also become Perry's second top five single in the United Kingdom, Australia, Ireland and New Zealand, and topped the charts in Finland, Germany, Canada, Norway, Spain and Denmark, and has topped the charts in 15 countries. As of September 2011, "Hot n Cold" has sold over five million digital downloads.