Cn1c(-c2c(C3=CC(=O)N(c4ccccc4)C3=O)c3ccccc3n2C)cc2ccccc21
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?