CC(=O)O[C@H]1CC[C@@]2(C)C(=CC[C@H]3[C@@H]4C[C@H](N5CCCC5)[C@H](OC(C)=O)[C@@]4(C)CC[C@@H]32)C1
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?