You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N'-[2-(1,1-dioxido-3,5-dihydro-2H-1lambda4,4-benzothiazepin-4-yl)-6-nitroquinolin-4-yl]ethane-1,2-diamine by IUPAC nomenclature, provide its molecular formula.
user
C20H21N5O4S-2
assistant