O=c1c2ccccc2[nH]c(=S)n1-c1ccc(/N=N/c2cccc3c(O)cccc23)cc1
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?