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 N-(2,3-dihydro-1H-inden-1-yl)-6-methyl-1-(2-nitrophenyl)-4-oxopyridazine-3-carboxamide is given. What is its corresponding molecular formula?
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C21H18N4O4
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