You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (5S,8S)-8-(2-iodo-4,5-dihydrobenzo[g][1,3]benzothiazol-7-yl)-2-oxaspiro[4.4]nonan-3-one by IUPAC nomenclature, provide its molecular formula.
user
C19H18INO2S
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