CCOC(=O)C1(NC(=O)C2(NC(=O)CN3C(=O)c4ccccc4C3=O)CCCC2)CCCC1
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?