O=[N+]([O-])c1ccc2c(Nc3ccccc3-c3ccccc3Nc3c4ccccc4nc4cc([N+](=O)[O-])ccc34)c3ccccc3nc2c1
A rotatable bond is defined as any single non-ring bond, attached to a non-terminal, non-hydrogen atom. How many bonds in the molecule are rotatable?