O=C(Cc1cccc(NC(=O)C2CCCN(C(=O)CCc3ccccc3)C2)c1)Nc1ccc(C(=O)N2CCOCC2)cc1
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?