You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(6-methoxyspiro[3,4-dihydroisochromene-1,4'-piperidine]-1'-carbonyl)-6-methylpyrido[1,2-a]pyrimidin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C24H25N3O4
assistant