You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl (3S)-3-(4-chlorophenyl)-3-[[(2R,3S)-2,3-dimethyl-2,3-dihydro-1-benzofuran-7-carbonyl]amino]propanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H22ClNO4
assistant