You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (3S)-1-[(2S)-1-[4-(hydroxymethyl)piperidin-1-yl]-4-methyl-1-oxopentan-2-yl]-3-(2-methylpropyl)piperazin-2-one by IUPAC nomenclature, provide its molecular formula.
user
C20H37N3O3
assistant