You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-bromo-4,6-dimethyl-1-[2-(4-methylpiperazin-1-yl)-2-oxoethyl]pyrimidin-2-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C13H19BrN4O2
assistant