You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named (E)-3-(3,4-dimethoxyphenyl)-N-[(7R)-5-oxo-7-phenyl-6,7-dihydro-4H-[1,2,4]triazolo[1,5-a]pyrimidin-2-yl]prop-2-enamide by IUPAC nomenclature, provide its molecular formula.
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C22H21N5O4
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