You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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(E)-but-2-enedioic acid;5-[(7,8-dimethoxy-2H-chromen-5-yl)methyl]pyrimidine-2,4-diamine is the IUPAC name of a molecule. Please give its molecular formula.
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C20H22N4O7
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