You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[3-(4-fluorophenyl)sulfanylpropyl]-3,4-dihydro-2H-1,5-benzodioxepine-7-sulfonamide by IUPAC nomenclature, provide its molecular formula.
user
C18H20FNO4S2
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