You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4,17,21-trichloropentacyclo[20.2.2.110,14.115,19.02,7]octacosa-1(24),2,4,6,10(28),11,13,15,17,19(27),20,22,25-tridecaene-5,13,16,24-tetrol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C28H19Cl3O4
assistant