You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[5-(3-fluorophenyl)-1,3,4-thiadiazol-2-yl]-2-(3-methoxyphenyl)-N-propylacetamide by IUPAC nomenclature, provide its molecular formula.
user
C20H20FN3O2S
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