You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[4-(2,3-dihydro-1,4-benzodioxine-6-carbonyl)-1,4-diazepan-1-yl]-2-(1H-pyrrol-3-yl)ethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H23N3O4
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