You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R)-3-(3-fluorobenzoyl)-5'-methoxy-1'-[(2-methylphenyl)methyl]spiro[1,3-thiazolidine-2,3'-indole]-2'-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C26H23FN2O3S
assistant