You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by N-[(6R)-3-cyano-6-ethyl-4,5,6,7-tetrahydro-1-benzothiophen-2-yl]-2-(4-ethylpiperazin-1-yl)acetamide ?
user
C19H28N4OS
assistant