You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(2,3-dichlorophenyl)-N-[3-[2-(dimethylamino)ethyl]-2-oxo-1,3-benzoxazol-5-yl]cyclopropane-1-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H21Cl2N3O3
assistant