O=C1c2c(O)cccc2C(C(=O)CCCCCC(=O)C2c3cccc(O)c3C(=O)c3c(O)cccc32)c2cccc(O)c21
A rotatable bond is defined as any single non-ring bond, attached to a non-terminal, non-hydrogen atom. How many bonds in the molecule are rotatable?