Oc1cc(O)c2c(c1)OC(c1ccc(O)c(O)c1)C(OC1(c3cc(O)c(O)c(O)c3)Oc3cc(O)cc(O)c3C(O)C1O)C2
A rotatable bond is defined as any single non-ring bond, attached to a non-terminal, non-hydrogen atom. How many bonds in the molecule are rotatable?