You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3R)-7-[2-(3-methylphenyl)ethyl]-5-oxo-8-phenyl-2,3-dihydro-[1,3]thiazolo[3,2-a]pyridine-3-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H21NO3S
assistant