CCCOC(=O)CCC(NC(=O)c1ccc(Nc2nc3ccccc3nc2-c2cccs2)cc1)C(=O)OCCC
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?