CC(=O)OCC1C(C(C)OC(C)=O)CCC2C1CCC1(C)C(OC(C)=O)CCC21
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?