You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 3-[(3,5-dichloro-2-ethylsulfonylphenyl)methyl]-6-(trifluoromethyl)quinazolin-4-one by IUPAC nomenclature, provide its molecular formula.
user
C18H13Cl2F3N2O3S
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