You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-[2,4-dioxo-5-(pyridin-3-ylmethylidene)-1,3-thiazolidin-3-yl]ethyl]-1-(thiophene-2-carbonyl)pyrrolidine-2-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H20N4O4S2
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