You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2,4-dichloro-N-[[(3S)-1-(4-fluorophenyl)-5-oxopyrrolidin-3-yl]methyl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H15Cl2FN2O2
assistant