You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (2S)-2-ethyl-2-methyl-1-[4-[(2S)-1-oxo-1-piperidin-1-ylpropan-2-yl]piperazin-1-yl]but-3-en-1-one ?
user
C19H33N3O2
assistant