You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named ethyl (5E)-4-hydroxy-2-imino-1-(4-nitrophenyl)-5-phenacylidenepyrrole-3-carboxylate is given. What is its corresponding molecular formula?
user
C21H17N3O6
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