You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (2R,6S)-4-[6-[6-(2-methoxyethoxy)-3H-isoindol-1-yl]pyrimidin-4-yl]-2,6-dimethylmorpholine into its molecular formula.
user
C21H26N4O3
assistant