O=C(c1ccccc1)[C@H]1[C@H](c2ccccc2)[C@@]2(N=C(c3ccccc3)OC2=O)C2c3ccccc3C=NN21
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?