CN(C)CCNC(=O)c1cccc2c(NC(CCCNC(=N)N)C(=O)O)c3ccccc3[n+](C)c12.COS(=O)(=O)[O-]
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?