O=C(OC1CO[C@H]2O[C@@H]1[C@H](OC(=O)c1ccccc1)[C@H]2OC(=O)c1ccccc1)c1ccccc1
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?