You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[1-(4-bromophenyl)imidazol-2-yl]sulfanyl-N-(1,3,5-trimethylpyrazol-4-yl)propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H20BrN5OS
assistant