You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4S)-1-methyl-N-[(1S)-1-[4-(3-methylbutoxy)phenyl]ethyl]-2-oxopiperidine-4-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H30N2O3
assistant