You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 3-[[3-bromo-4-(difluorooxyphosphorylmethyl)phenyl]methyl]-4-(4-methylsulfonylphenyl)-2-oxoimidazole-1-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H20BrF2N2O8PS
assistant