You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2,6-dichloro-N-[4-(3-cyanopyridin-2-yl)oxy-2-methylphenyl]pyridine-3-sulfonamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H12Cl2N4O3S
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