You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[(5Z)-5-[[4-methoxy-3-[(2-nitrophenoxy)methyl]phenyl]methylidene]-4-oxo-2-sulfanylidene-1,3-thiazolidin-3-yl]butanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H20N2O7S2
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