You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7-(1-bromo-2-methyl-2-methylsulfonylpropyl)-3-methyl-3,4-dihydro-2H-1,5-benzodioxepine is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H21BrO4S
assistant