You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-(3,4-dimethoxyphenyl)-2-[(1R,5R)-3-hydroxy-3-(1-methylimidazol-2-yl)-8-azabicyclo[3.2.1]octan-8-yl]acetamide into molecular formula.
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C21H28N4O4
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