O=c1cc(-c2ccccc2)oc2cc(O[C@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@@H]3O)c(O)c(O)c12
A rotatable bond is defined as any single non-ring bond, attached to a non-terminal, non-hydrogen atom. Amide C-N bonds are not counted because of their high barrier to rotation.  How many rotatable bonds does the molecule have?