Br.COc1cccc(Nc2nc(-c3cccc(N4C(=O)c5ccccc5C4=O)c3)cs2)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?