You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 4-[2-fluoro-5-[(Z)-2-fluoro-2-(5-pent-1-ynylpyridin-2-yl)ethenyl]phenyl]-6-methyl-5,6-dihydro-4H-1,3-thiazin-2-amine by IUPAC nomenclature, provide its molecular formula.
user
C23H23F2N3S
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