You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-1-[2-[(5,7-dimethyl-[1,2,4]triazolo[4,3-a]pyrimidin-3-yl)sulfanyl]acetyl]piperidine-2-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H20N6O2S
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