O=C(Nc1cccc2ccccc12)c1[nH]c(-c2ccccc2)c2c1C(=O)N(C1CC1)C2=O
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?