You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-(2-cyanophenyl)-2-[(4S)-4-thiophen-2-yl-4,5,6,7-tetrahydrothieno[3,2-c]pyridin-5-ium-5-yl]acetamide into molecular formula.
user
C20H18N3OS2+
assistant