CCCCCc1c2nc(c(CCCCC)c3ccc([nH]3)c(CCCCC)c3nc(c(CCCCC)c4ccc1[nH]4)C=C3)C=C2
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?