You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-[(3R)-2,2-dimethyl-1-azabicyclo[2.2.2]octan-3-yl]-1-(7-methyl-1-benzothiophen-2-yl)ethanone .
user
C20H25NOS
assistant