COc1cc(-c2coc3cc(OCc4ccccc4)c(OC)c(O)c3c2=O)cc(O)c1OC
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?