COC(=O)c1cccc(Oc2nc3c(c(=O)n(C)c(=O)n3C)n2Cc2ccc(C)cc2)c1
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?