O=c1c2cc3c(=O)n4c(cc(-c5ccccc5)c5cc(Cl)ccc54)nc3cc2nc2cc(-c3ccccc3)c3cc(Cl)ccc3n12
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?