You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-(1,3-benzothiazol-2-yl)-2-[[5-(2-fluorophenyl)-4-prop-2-enyl-1,2,4-triazol-3-yl]sulfanyl]propanamide by IUPAC nomenclature, provide its molecular formula.
user
C21H18FN5OS2
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