cnblue dont have a song with a 제목 "What's Up". but from what i know what's up song is sang 의해 four blondes and the song were sang 의해 seohyun on wgm, while she's learning 기타 from Yonghwa wh.Yonghwa asked her to practiced that song:).but cnblue dont have a song called "what's up" : )