CCc1c(O)c2c(c(O)c1C(C)=O)C(=O)c1c(cc(O)c(C(=O)O)c1C(=O)O)C2=O
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?