You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named methyl 18-chloro-5-oxo-16-oxa-4,10-diazatricyclo[15.2.2.06,10]henicosa-1(19),13,17,20-tetraene-3-carboxylate is given. What is its corresponding molecular formula?
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C20H25ClN2O4
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