O=C1C[C@@H]2[C@@H](C[C@H](OC(=O)c3ccc(-c4ccccc4)cc3)[C@H]2CO)O1
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?