C#CCOCCOCCOCCNc1nc(N2CCOCC2)nc(N2CCN(C(=O)[C@H](CCC(=O)O)n3cc(C(N)[C@H](C)CC)nn3)CC2)n1.Cl
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?