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 2-[(1-quinoxalin-2-ylpyrrolidin-2-yl)methyl]-7,8-dihydro-5H-thiopyrano[4,3-c]pyridazin-3-one .
user
C20H21N5OS
assistant