O=C1C2=C(CC3C(C2)C3(Br)Br)C(=O)C2=C1CC1C(C2)C1(Br)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?