COc1ccc2c(c1)c1c(c(=O)n(-c3ccccc3C)c(=O)n1Cc1ccccc1C)n2C
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?