COC(=O)C(C(=O)C(=O)Nc1c(Cl)cc([N+](=O)[O-])cc1Cl)c1csc(-n2nc(C3=CCCCC3)cc2-c2ccccc2)n1
Heavy atom refers to any atom that is not hydrogen. The heavy atoms in molecules are carbon, oxygen, nitrogen, and sulfur. How many heavy atoms are in the molecule?