You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (15R)-5-[[4-fluoro-6-(3-methyloxetan-3-yl)oxypyrimidin-2-yl]amino]-15-methyl-11-thia-6,14,17-triazatetracyclo[8.8.0.02,7.012,18]octadeca-1(10),2(7),3,5,8,12(18)-hexaen-13-one into molecular formula.
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C23H21FN6O3S
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