You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-[2-(9H-fluoren-9-ylmethoxycarbonylamino)propanoyl]-6-azaspiro[3.4]octane-8-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C26H28N2O5
assistant