You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-propan-2-yl-2,3,3a,4,6,7-hexahydro-[1,2,5]thiadiazolo[2,3-a]pyrazine 1,1-dioxide is the IUPAC name of a molecule. Please give its molecular formula.
user
C8H17N3O2S
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