You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[4-(difluoromethoxy)phenyl]-2-[(4-methoxy-3,5-dimethylphenyl)methyl-methylamino]propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26F2N2O3
assistant