You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 1-[4-[1-(2-methylpropanoyl)-2,3-dihydroindol-5-yl]benzoyl]piperidine-4-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C27H32N2O4
assistant