You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 8-[(2-amino-2-methylpropyl)-methylamino]-7-but-2-ynyl-3-methyl-1-[(4-methylquinazolin-2-yl)methyl]-2H-purin-6-one by IUPAC nomenclature, provide its molecular formula.
user
C25H32N8O
assistant