You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-(2-fluorophenyl)-5-methyl-6-methylsulfanylpyrazolo[1,5-a]pyrimidin-7-yl]piperidine-3-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H21FN4O2S
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