You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(2,5-dimethyl-1H-pyrrol-3-yl)-2-(7,7-dimethyl-1,4-thiazepan-4-yl)ethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H24N2OS
assistant