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system
Name the molecular formula for the molecule established as (1R,12R)-3,16-dimethoxy-20-methyl-5,7-dioxa-20-azapentacyclo[10.5.3.01,13.02,10.04,8]icosa-2,4(8),9,16-tetraen-15-one using the IUPAC nomenclature.
user
C20H23NO5
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