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 3-(1,4-dioxa-8-azaspiro[4.5]decan-8-yl)-N-[2-(2-fluorophenyl)ethyl]-3-oxopropanamide into molecular formula.
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C18H23FN2O4
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