In the following circuit \( C_1 = 12\,\mu\mathrm{F} \), \( C_2 = C_3 = 4\,\mu\mathrm{F} \) and \( C_4 = C_5 = 2\,\mu\mathrm{F} \). The charge stored in \( C_3 \) is ____ \( \mu\mathrm{C} \).
