C#CCCOC(=O)N1C2=NC(C(=O)OC)=C(C(=O)OC)[C@@H]3N(CC=C)c4ccccc4[C@]23C[C@H]1C(=O)OC
Hydrogen bond acceptor is the chemical compound which contains the lone electron pairs that participate in the hydrogen bond formation. How many hydrogen bond acceptors does the molecule contain?