Cc1cc(C(C)(C)C)cc(Cc2cc(C(C)(C)C)cc(Cc3cc(C(C)(C)C)cc(C)c3O)c2O)c1O
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?