You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 2-methyl-8-(2-methylbutan-2-yl)-2,3,4,5,5a,6,7,8,9,9a-decahydrobenzo[b][1,4]thiazepine .
user
C15H29NS
assistant