O=C(c1ccccc1)[C@H]1[C@H](c2ccccc2)[C@@]2(N=C(c3ccccc3)OC2=O)C2c3ccccc3C=NN21
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?