You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1R)-N-[(2-chloro-4,5-dimethoxyphenyl)methyl]-2-methoxy-N-methyl-1-pyridin-2-ylethanamine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H23ClN2O3
assistant