You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[[2-amino-4-(cyclohexylmethyl)-1-methyl-5-oxoimidazol-4-yl]methyl]-2,3-dihydroquinolin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H28N4O2
assistant