S=C([S-])O[C@@H]1C[C@@H]2C[C@H]1[C@@H]1CCC[C@H]21.[K+]
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?