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 (2R)-3-[(1S,2S,4S)-2-bicyclo[2.2.1]heptanyl]-3-oxo-2-(4-oxo-5,6,7,8-tetrahydro-3H-[1]benzothiolo[2,3-d]pyrimidin-2-yl)propanenitrile .
user
C20H21N3O2S
assistant