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 (6aS)-6a-ethyl-5-methyl-2-[2-(3-pyridin-3-ylphenyl)imidazol-1-yl]-8,9-dihydro-7H-pyrrolo[2,1-h]pteridin-6-one ?
user
C26H25N7O
assistant