O=C(Nc1nc2ncn(CCNCCn3cnc4nc(NC(=O)c5ccccc5)[nH]c(=O)c43)c2c(=O)[nH]1)c1ccccc1
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?