You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(3,5-dichlorophenyl)-2-[6-methyl-7-(4-methylphenyl)-2-oxo-1,3-dihydroimidazo[1,2-b]pyrazol-3-yl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H18Cl2N4O2
assistant