You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
8-[[(1R,2S)-2-aminocyclohexyl]amino]-7-[(2-bromophenyl)methyl]-3-methyl-1-phenacylpurine-2,6-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C27H29BrN6O3
assistant