You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-(dimethylamino)ethyl]-4-(10-methoxy-2,3,4,6-tetrahydro-1,5-benzoxazocine-5-carbonyl)pyrrolidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H29N3O4
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