You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (3R)-3-acetamido-N-[(2S)-1-imidazol-1-ylpropan-2-yl]-3-(4-methylphenyl)propanamide by IUPAC nomenclature, provide its molecular formula.
user
C18H24N4O2
assistant