COc1c(-c2coc3cc4c(cc3c2=O)CC(OC(C)=O)C(C)(C)O4)ccc2c1C=CC(C)(C)O2
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?