You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 4-methoxy-3-methyl-N-[(2R)-2-(4-methylpiperazin-1-yl)-2-pyridin-3-ylethyl]benzenesulfonamide into its molecular formula.
user
C20H28N4O3S
assistant