You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-2-[(5E)-5-benzylidene-4-oxo-2-sulfanylidene-1,3-thiazolidin-3-yl]-N-[(3R)-1,1-dioxothiolan-3-yl]-N-methylpropanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H20N2O4S3
assistant