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-[[(3aS,6aR)-3-(3-chlorophenyl)-5,5-dioxo-3a,4,6,6a-tetrahydrothieno[3,4-d]imidazol-2-yl]sulfanylmethyl]-3H-quinazolin-4-one .
user
C20H17ClN4O3S2
assistant