You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-(6,7-dihydro-4H-thieno[3,2-c]pyridin-5-yl)-2-(3,4-dimethylphenyl)ethanone by IUPAC nomenclature, provide its molecular formula.
user
C17H19NOS
assistant