You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[4-[7-[(4-bromophenyl)methyl]-1,3-dimethyl-2,6-dioxopurin-8-yl]piperazin-1-yl]-N-(2,4-dimethoxyphenyl)acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H32BrN7O5
assistant