You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(7-pyrrolidin-1-ylsulfonyl-3,4-dihydro-1H-isoquinolin-2-yl)-[(2S)-spiro[2.4]heptan-2-yl]methanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H28N2O3S
assistant