You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1,3-dimethyl-7-(2-oxo-2-spiro[3,4-dihydrochromene-2,4'-piperidine]-1'-ylethyl)purine-2,6-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H25N5O4
assistant