KOREAN ONF (온앤오프) ONF – Difficult Difficult “Difficult” [EP] ON/OFF 2017.08.02 Hyojin, E-Tion, J-US, Wyatt, MK, U, Laun Lyrics/작사: 황현 (MonoTree) Composer/작곡: 황현 (MonoTree), Paulo Jonson Arranger/편곡:…