You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule propan-2-yl 2-[(2,4-dichlorobenzoyl)amino]-5-(diethylcarbamoyl)-4-methylthiophene-3-carboxylate into molecular formula.
user
C21H24Cl2N2O4S
assistant