S=c1nc(Nc2ccc(Br)cc2)c2c3c(sc2[nH]1)CN(N1CCc2c(sc4[nH]c(=S)nc(Nc5ccc(Br)cc5)c24)C1)CC3
Hydrogen bond acceptor is the chemical compound which contains the lone electron pairs that participate in the hydrogen bond formation. This compound should contain a more electronegative atom (more electronegative than hydrogen) with lone electron pairs. Then it can attract protons from a donor. Moreover, the electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?