You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2,3-dihydro-1,4-benzodioxin-5-yl-[2-(piperidin-1-ylmethyl)-1,4-oxazepan-4-yl]methanone into molecular formula.
user
C20H28N2O4
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