You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 4-[(2R)-1-(4-fluorophenyl)sulfonylpyrrolidin-2-yl]-N-pyrazin-2-ylpyrimidin-2-amine into molecular formula.
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C18H17FN6O2S
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