You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance [4-(5-chloro-2-methylphenyl)piperazin-1-yl]-[(2S)-2-fluoro-2-(4-fluorophenyl)cyclopropyl]methanone .
user
C21H21ClF2N2O
assistant