You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 8-[(3-chlorophenyl)-phenylmethyl]-4-hydroxy-6-methyl-7,8-dihydropyrazino[1,2-b]pyridazine-3,5-dione ?
user
C21H18ClN3O3
assistant