O=C(c1ccccc1)c1nnn(Cc2ccccc2Cn2nnc(C(=O)c3ccccc3)c2C(=O)c2ccccc2)c1C(=O)c1ccccc1
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?