NEW YORK (Reuters) - R&B artist Bruno Mars won the top prize at the Grammy Awards on Sunday, denying rappers Kendrick Lamar and Jay-Z the honor of becoming the first hip-hop artist in 14 years to win the coveted album of the year award. Mars won six Grammys including song of the year for his hit single ?That?s What I Like,? and both record and album of the year for ?24K Magic.?