You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluorooctane-1-sulfonate;1-(3-methylthian-1-ium-1-yl)butan-2-one into molecular formula.
user
C18H19F17O4S2
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