You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 1-[(1S)-1-(2,5-difluorophenyl)ethyl]-1-methyl-3-(3-phenyl-1,2,4-thiadiazol-5-yl)urea by IUPAC nomenclature, provide its molecular formula.
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C18H16F2N4OS
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