You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name (1-acetamido-7-chloro-2,3,5,6,7,8-hexahydro-1H-pyrrolizin-2-yl) N-methyl-N-(2-oxa-6-azatricyclo[4.2.1.03,7]nonan-8-yl)carbamate into its molecular formula.
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C18H27ClN4O4
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