You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-chloro-5-ethoxy-4-hydroxy-N-[(4-methoxyphenyl)-(1-methylimidazol-2-yl)methyl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H22ClN3O4
assistant