COc1cc2c(=O)c(-c3ccc(O)cc3)coc2cc1OC1OC(CO)C(O)C(O)C1O
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?