CC1=C(C(=O)Nc2ccc([N+](=O)[O-])cc2)C(c2cccc([N+](=O)[O-])c2)C(C(=O)Nc2ccc([N+](=O)[O-])cc2)=C(C)N1
All atoms other than hydrogen are referred to be heavy atoms. How many heavy atoms are there in the molecule?