You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl 2-[5-[(4-ethoxyphenyl)methylidene]-2,4-dioxo-1,3-thiazolidin-3-yl]acetate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H21NO5S
assistant