Question: Who was a writer on both "Roc Me Out" and "S&M", songs recorded by Barbadian recording artist Rihanna?
Context: "Watch n' Learn" is a song recorded by Barbadian recording artist Rihanna, for her sixth studio album "Talk That Talk" (2011).  It was written by Chauncey Hollis and Rihanna.  The production was done by Hollis under his stage-name Hit-Boy.  When Renea came with an idea and concept for the song, Hollis had already started working on the composition, without having in mind any particular artist.  With the work on the track being finished, it was forwarded to Rihanna and her label, which eagerly accepted it. "You da One" is a song by Barbadian recording artist Rihanna recorded for her sixth studio album, "Talk That Talk" (2011).  It was co-written by Rihanna with Ester Dean, Henry Walter, John Hill and Lukasz Gottwald.  Production of the song was completed by Gottwald, under his production name Dr. Luke, and Cirkut.  Kuk Harrell and Marcas Tovar recorded the track at the Sofital Paris Le Laubourg, Room 538, and Westlake Recording Studios in Los Angeles, California.  It premiered on US radio on November 11, 2011, and was made available to download digitally throughout Europe and Australasia on November 14, 2011.  It was added to US Mainstream, rhythmic and urban radio station playlists on November 29, 2011.  Throughout December 2011 and January 2012, a remix extended play (EP) was released worldwide. "Bad Girl" is a song initially recorded by Barbadian recording artist Rihanna and American recording artist Chris Brown for the soundtrack of the film "Confessions of a Shopaholic" (2009).  Their version of the song was excluded from the soundtrack, in favor of a version performed by the American girl group The Pussycat Dolls.  Rihanna and Brown's version of the song was leaked on the internet on January 6, 2009.  The song is about an addiction to shopping, and more specifically, buying shoes and handbags.  Hollywood Records' decision to not include Rihanna and Brown's version was criticized by Ryan Brockington for the "New York Post", but Michael Quinn for BBC Music was complimentary of The Pussycat Dolls' version.  Rihanna and Brown's version charted at number 55 on the US Hot R&B/Hip-Hop Songs. "Skin" is a song by Barbadian recording artist Rihanna from her fifth studio album, "Loud" (2010).  The song was written by Kenneth Coby and Ursula Yancy, with production helmed by Soundz.  Musically, "Skin" is a R&B song that contains influences from pop, dance-pop and dubstep genres, whilst lyrically, the song is about being in a relationship with someone and only wanting to feel their skin close to the protagonists.  "Skin" received generally positive reviews from critics, as part of their overall review of "Loud", praising "Skins compositions as well as Rihanna's sensual vocal performance.  The song was included on the set list of the Loud Tour (2011), where Rihanna retrieves a man or woman from the audience near the end of the song, and performs a lap-dance whilst on an elevated platform.  "Skin" was also used in Rihanna's advertisement campaign for Armani Jeans. "S&M" is a song by Barbadian singer Rihanna from her fifth studio album, "Loud" (2010).  The song was released on January 21, 2011, as the fourth single from the album.  The American songwriter Ester Dean wrote "S&M" in collaboration with the producers Stargate and Sandy Vee.  Backed by bass beats, a keyboard and guitars, it is an uptempo hi-NRG-Eurodance track with lyrics that revolve around sexual intercourse, sadomasochism, bondage, and fetishes. One Love is the fourth studio album by French DJ David Guetta, first released in the United Kingdom on 24 August 2009 through Virgin Records.  Guetta's first major international release, the album received generally favourable reviews from music critics, and was a commercial success, selling over 3 million copies globally.  It spawned a total of six worldwide hit singles throughout 2009 and 2010, most notably "When Love Takes Over", featuring American recording artist Kelly Rowland, "Sexy Bitch", featuring Senegalese-American R&B singer Akon, and "Who's That Chick? ", featuring Barbadian recording artist Rihanna and "One Love", featuring British recording artist Estelle.  "One Love" is also Guetta's last studio album to feature his long-time collaborator, Chris Willis, on vocals.  Since the album's initial release it has since been reissued several times to include previously unreleased tracks and other bonus material. Barbadian recording artist Rihanna has embarked on four concert tours, three of which have been worldwide.  Her 2006 debut, was based in North America only and supported her first and second studio album, "Music of the Sun" (2005) and "A Girl like Me" (2006).  The tour lasted for three months, through which Rihanna performed 36 shows.  The same year, Rihanna continued to tour as a special guest on the PCD World Tour with Pussycat Dolls, Roc the Block Tour with Jay-Z and Ne-Yo, and the Monkey Business Tour with Black Eyed Peas.  In the period from 2007 till 2009, she performed on the worldwide Good Girl Gone Bad Tour in a support of her third studio album with same name.  During the tour, Rihanna visited Europe, North America, Oceania, Asia and Africa.  It featured Rihanna presenting completely different style and wearing leather outfits.  The Good Girl Gone Bad Tour sparked controversy in Malaysia where the Pan-Malaysian Islamic Party recommended that Rihanna's concert tour should be banned due her provocative outfits.  A DVD, titled "Good Girl Gone Bad Live" was released on June 16, 2008.  It features the show from Evening News Arena in Manchester, England, held on December 6, 2007. "Phresh Out the Runway" (also known as "Fresh Off the Runway") is a song recorded by Barbadian recording artist Rihanna for her seventh studio album "Unapologetic" (2012).  It was co-written by Rihanna with French disc-jockey David Guetta, Giorgio Tuinfort and Terius Nash.  It is the first time that Rihanna and Guetta had collaborated since "Who's That Chick? ", released in November 2010.  "Phresh Out the Runway" is a hip hop and rave song that contains heavy synthesizers and bass.  Lyrically, Rihanna explains how if any of her crew does not respect her, they should no longer remain with her. The Loud Tour was the fourth overall and third world concert tour by Barbadian recording artist Rihanna.  Performing in over twenty countries in the Americas and Europe, the tour was launched in support of Rihanna's fifth studio album "Loud" (2010) but eventually supported her following album "Talk that Talk" as it was released during the tour, in November 2011.  Critics acclaimed the show for its liveliness and higher caliber of quality when compared to Rihanna's previous tours.  The Loud Tour was a large commercial success, experiencing demand for an extension of shows in the United Kingdom due to popularity.  In London, Rihanna played a record breaking 10 dates at The O2 Arena.  The tour ultimately grossed an estimated value of US$90 million from 98 reported shows and a total audience of 1,200,800.  The Loud Tour became the 7th highest grossing tour of 2011. "Roc Me Out" is a song recorded by Barbadian recording artist Rihanna for her sixth studio album "Talk That Talk" (2011).  It was written by Ester Dean, Robert Swire, Gareth McGrillen, Mikkel S. Eriksen and Tor Erik Hermansen.  The track was produced by StarGate (Eriksen and Hermansen) and Knife Party (Swire and McGrillen).  "Roc Me Out" is a synthpop-influenced R&B song reminiscent of Rihanna's previous singles "Rude Boy" and "S&M".  It is set in "chugging" tempo and features heavy synths, "contagious" hooks and West Indian nuances.  Lyrically, the song features Rihanna sexually seducing her lover, while revealing her "nasty secrets".  Contemporary music critics were divided in their reviews of "Roc Me Out"; some of them labeled the song as a highlight on the album, while others criticized its similarity to Rihanna's previous singles.  Upon the release of "Talk That Talk", the song debuted on the lower regions of the singles charts in South Korea and the United Kingdom at number 73 and 176 respectively.
Answer: Ester Dean