You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(2S)-2-[1-(difluoromethyl)benzimidazol-2-yl]propyl]-2,3-dimethyl-5-nitrobenzenesulfonamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H20F2N4O4S
assistant