O=C(O)CCN1C(=O)c2ccc(Oc3ccc4c(c3)C(=O)N(CCC(=O)O)C4=O)cc2C1=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?