You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-(2-ethoxy-N-methylsulfonylanilino)-N-[(2R)-1-(4-methoxyphenoxy)propan-2-yl]acetamide by IUPAC nomenclature, provide its molecular formula.
user
C21H28N2O6S
assistant