O=c1[nH]c2c(N/N=C/c3ccc([N+](=O)[O-])o3)c([N+](=O)[O-])c(N/N=C/c3ccc([N+](=O)[O-])o3)c([N+](=O)[O-])c2[nH]1
All atoms other than hydrogen are referred to be heavy atoms. How many heavy atoms are there in the molecule?