Cc1ccc(C(=O)C[n+]2cc(-c3ccccc3)n3c2CCCCC3)cc1.[Br-]
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?