O=C(O)c1cc(O)c2c(c1)[C@H]([C@H]1c3cc(C(=O)O)cc(O)c3C(=O)c3c(O[C@@H]4OC(CO)C(O)C(O)C4O)cccc31)c1cccc(O[C@@H]3OC(CO)C(O)C(O)C3O)c1C2=O
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?