Oc1ccc2c3c1O[C@H]1c4c(c5ccccc5n4Cc4ccccc4)C[C@]4(O)[C@H](C2)N(CC2CC2)CC[C@@]314
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?