O=C(/C=C\c1ccccc1)Oc1ccc(/C=C2\CCC/C(=C\c3ccc(OC(=O)/C=C\c4ccccc4)cc3)C2=O)cc1
Hydrogen bond acceptor: The atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom. How many hydrogen bond acceptors does the molecule have?