You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule N-[2-[(8R)-2-[(1-methylpyrazol-4-yl)methyl]-5-oxa-2-azaspiro[3.4]octan-8-yl]ethyl]ethanesulfonamide into molecular formula.
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C15H26N4O3S
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