You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7-(2,4-dimethoxybenzoyl)-1-(3-fluorophenyl)-3-methoxy-1,7-diazaspiro[3.5]nonan-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H25FN2O5
assistant