O=Cc1ccccc1COC(=O)c1cc(C(=O)OCc2ccccc2C=O)c(C(=O)OCc2ccccc2C=O)cc1C(=O)OCc1ccccc1C=O
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?