You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(2S)-1-(6,7-dihydro-4H-thieno[3,2-c]pyridin-5-yl)-3-methyl-1-oxobutan-2-yl]-3,5-dimethoxybenzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26N2O4S
assistant