You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[5-(azepan-1-ylsulfonyl)-2-methoxyphenyl]-2,3-dihydro-1-benzofuran-5-sulfonamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26N2O6S2
assistant