COC(=O)Cn1nc(-c2ccc(C)c(S(=O)(=O)N(C)C)c2)c2ccccc2c1=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?