O=c1c(O)c(-c2cc(O)c(O)cc2O)oc2cc(O)c(C3OC(CO)C(O)C(O)C3O)c(O)c12
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?