Question: Which brand of music are American vocalist Sammy Hagar, and South Korean musician Jung Yong-hwa known for?
Context: Do Disturb is the first mini-album by South Korean musician and CNBLUE member Jung Yong-hwa.  It was released in July 19, 2017, under FNC Entertainment.  Its titled was inspired by a "do not disturb" door hanger.  Consisting of dance music tracks and balladry, the record sees a sonic shift from Jung's previous music with his band and as a solo artist. Montrose is the debut album by the American hard rock band Montrose released in 1973 on the Warner Bros. label.  It was produced by Ted Templeman.  The album marks the recording debut of vocalist Sammy Hagar, who would later achieve international success as a solo artist and member of Van Halen. Samuel Roy Hagar (born October 13, 1947), also known as The Red Rocker, is an American rock vocalist, guitarist, songwriter, musician and entrepreneur.  Hagar came to prominence in the 1970s with the hard rock band Montrose.  He afterwards launched a successful solo career, scoring an enduring hit in 1984 with "I Can't Drive 55".  He enjoyed huge commercial success when he replaced David Lee Roth as the lead singer of Van Halen in 1985, but left the band in 1996.  He returned to the band for a 2-year reunion from 2003 to 2005.  On March 12, 2007, Hagar was inducted into the Rock and Roll Hall of Fame as a member of Van Halen.  His musical style primarily consists of hard rock and heavy metal. Jung Yong-hwa (; ] ; born June 22, 1989) is a South Korean musician, singer-songwriter, record producer and actor.  He is the leader, lead vocalist and rhythm guitarist of the rock band CNBLUE.  Jung made his television debut in "You're Beautiful" (2009), and has since starred in television dramas "Heartstrings" (2011), "Marry Him If You Dare" (2013) and "The Three Musketeers" (2014).  In 2015, Jung made his solo debut with the album "One Fine Day". Hagar Schon Aaronson Shrieve (also known as HSAS) was a band featuring lead vocalist Sammy Hagar, lead guitarist Neal Schon, bassist Kenny Aaronson and drummer Michael Shrieve.  The group reportedly rehearsed for less than a month before playing in concert.  They released a semi-live album, recorded during two live performances at The Warfield in San Francisco, entitled "Through the Fire".  The album includes a cover of Procol Harum's "A Whiter Shade of Pale". OU812 (pronounced "Oh You Ate One Too") is the eighth studio album by American hard rock band Van Halen, released in 1988, and the second to feature vocalist Sammy Hagar.  Van Halen started work on the album in September 1987 and completed it in April 1988, just one month before its release. "Right Now" is a rock song written by the group Van Halen for their album "For Unlawful Carnal Knowledge".  The song reflects on living for the moment and not being afraid of making a change.  Vocalist Sammy Hagar has said that he was writing the lyrics to this song at the studio very late one night, and he heard Eddie Van Halen in an adjacent room working on a piano melody.  Hagar said he suddenly realized that "we were writing the same song," so he walked into the room and began singing his words over Van Halen's music.  According to Eddie, the instrumental dates back to 1983, "before I wrote "Jump" - it didn't come out until about '92, '93 or something like that, cause nobody wanted anything to do with it."  An early version of the melody appears in the 1984 movie "The Wild Life" which was scored by Eddie Van Halen.  Eddie also stated that before Hagar was hired to replace David Lee Roth, he considered an album that would feature various guest singers, with Joe Cocker assigned to "Right Now". Summer Calling is the second Japanese studio album by South Korean musician and CNBLUE member Jung Yong-hwa.  It was released on August 9, 2017, under Warner Music Japan in three editions: Regular Edition, Limited Edition, and a fan club-only Boice Limited Edition. Paper Money (1974) is the second album by the American hard rock band Montrose.  It was produced by Ted Templeman and is the band's final recording with original vocalist Sammy Hagar.  It marks the arrival of new bass player Alan Fitzgerald, replacing original bassist Bill Church. "You, My Star" (별, 그대 ; "Byeol, Geudae " ) is a song by South Korean musician Jung Yong-hwa of CNBLUE.  Written in dedication to his fans, the song was released in December 23, 2013, under FNC Entertainment.  Two days prior, Jung performed the song on the year-end music program "SBS Gayo Daejeon".  "You, My Star" debuted and peaked at number 22 no South Korea's national Gaon Digital Chart; all proceeds went to the label's charity Love FNC.
Answer: rock