You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (3R,4S)-N-[2-[(2-fluorophenyl)methylsulfanyl]ethyl]-4-(1-methylpyrazol-4-yl)pyrrolidine-3-carboxamide .
user
C18H23FN4OS
assistant