You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(4-benzylpiperazin-1-yl)-4-[1-(3-methoxyphenyl)-3,4-dihydro-1H-pyrrolo[1,2-a]pyrazin-2-yl]butane-1,4-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C29H34N4O3
assistant