O=C1C2C(C(=O)N1c1ccccc1)C1(Br)c3ccccc3C2(Br)C2C(=O)N(c3ccccc3)C(=O)C21
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?