You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule (3S)-3'-(4-chlorophenyl)-6-fluoro-2,5'-dioxospiro[1H-indole-3,7'-4,6-dihydrothieno[3,2-b]pyridine]-2'-carboxylic acid ?
user
C21H12ClFN2O4S
assistant