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 [4-butoxy-6,7-dichloro-2-(furan-2-ylmethyl)-1-oxoisoquinolin-3-yl]-methylcarbamic acid is given. What is its corresponding molecular formula?
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C20H20Cl2N2O5
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