COc1ccc(-n2c(=O)c3c(c4cc(OC)ccc4n3C)n(CCC(C)C)c2=O)cc1
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?