You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance ethyl (4R,6R,7S)-2,5-dioxo-7-thiophen-2-yl-4-thiophen-3-yl-1,3,4,6,7,8-hexahydroquinoline-6-carboxylate .
user
C20H19NO4S2
assistant