You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named (4R,4aS,12bS)-7a,10,11-trideuterio-4a-deuteriooxy-9-methoxy-3-(trideuteriomethyl)-1,2,4,5,6,13-hexahydro-4,12-methanobenzofuro[3,2-e]isoquinolin-7-one is given. What is its corresponding molecular formula?
user
C18H21NO4
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