CCC(=O)C(C)C1=Nc2nnc(CCCCCCCc3nnc4n3C(=O)C(C(C)C(=O)CC)=N4)n2C1=O
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?