You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name 2-phenyl-7-[3-(9-phenylcarbazol-3-yl)-9H-fluoren-9-yl]pyrido[1,2-a][1,3,5]triazin-4-one ?
user
C44H28N4O
assistant