You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(E)-2-chloro-3-(2,5-dimethoxyphenyl)-1-[3-(dimethylamino)-4-methoxyphenyl]prop-2-en-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H22ClNO4
assistant