CCOC(=O)c1c(N2CCCC2)[nH]c(=O)c(C(c2ccc(Cl)c([N+](=O)[O-])c2)c2c(O)c(C(=O)OCC)c(N3CCCC3)[nH]c2=O)c1O
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?