You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R)-2-[5-(azepan-1-ylsulfonyl)-2-methoxyanilino]-N-(3-cyanothiophen-2-yl)propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26N4O4S2
assistant