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 [8-(oxan-4-ylmethoxy)-5-oxa-2-azaspiro[3.5]nonan-2-yl]-thiophen-2-ylmethanone is given. What is its corresponding molecular formula?
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C18H25NO4S
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