O=C(OC[C@@H]1O[C@@](O)(COC(=O)c2cccnc2)[C@H](OC(=O)c2cccnc2)[C@H]1OC(=O)c1cccnc1)c1cccnc1
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?