Cn1cc(C[C@H](C(=O)O)N2C(=O)c3ccc(C(=O)O)cc3C2=O)c2ccccc21
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?