O=C(Cc1cccc(NC(=O)C2CCN(C(=O)C3CCCCC3)CC2)c1)Nc1cccc(C(=O)N2CCCCC2)c1
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?