You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-[4-[5-fluoro-1-(4-fluorophenyl)indol-3-yl]piperidin-1-yl]ethyl]pyrrolidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C25H27F2N3O
assistant