You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named tert-butyl 4-ethoxy-2-(4-fluorophenyl)-1-oxa-9-azaspiro[5.5]undecane-9-carboxylate;dichloromethane;4-ethoxy-2-(4-fluorophenyl)-1-oxa-9-azaspiro[5.5]undecane by IUPAC nomenclature, provide its molecular formula.
user
C40H58Cl2F2N2O6
assistant