You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3aS,7aS)-2-[4-(4-fluorophenoxy)butanoyl]-1,3,3a,4,6,7-hexahydropyrano[3,4-c]pyrrole-7a-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H22FNO5
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