O=C1C(OC(=O)c2ccccc2)=C(c2ccc(O)cc2)C(=O)C(OC(=O)c2ccccc2)=C1c1ccc(O)cc1
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?