Consider the following molecules: \( \mathrm{Br_3O_8} \), \( \mathrm{F_2O} \), \( \mathrm{H_2S_4O_6} \), \( \mathrm{H_2S_5O_6} \) and \( \mathrm{C_3O_2} \). Count the number of atoms existing in their zero oxidation state in each molecule. Their sum is \( \_\_\_\_\_ \).
