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 6-[(3,5-dimethoxyphenyl)methyl]-2-pyridin-4-yl-3,5,7,8-tetrahydropyrido[4,3-d]pyrimidin-4-one is given. What is its corresponding molecular formula?
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C21H22N4O3
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