O=C1N=C(N2CCOCC2)S/C1=C/c1cc2c(cc1[N+](=O)[O-])OCO2
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?