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 (3aR,6aR)-2-[(2,6-dichlorophenyl)methylsulfanyl]-3-(3,4-dimethoxyphenyl)-3a,4,6,6a-tetrahydrothieno[3,4-d]imidazole 5,5-dioxide .
user
C20H20Cl2N2O4S2
assistant