You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-2-[4-[(3R)-1,1-dioxothiolan-3-yl]piperazin-1-yl]-2-(6-fluoro-1H-indol-3-yl)acetic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H22FN3O4S
assistant