Wires $$W_1$$ and $$W_2$$ are made of same material having the breaking stress of $$1.25 \times 10^9$$ N m$$^{-2}$$. $$W_1$$ and $$W_2$$ have cross-sectional area of $$8 \times 10^{-7}$$ m$$^2$$ and $$4 \times 10^{-7}$$ m$$^2$$, respectively. Masses of 20 kg and 10 kg hang from them as shown in the figure. The maximum mass that can be placed in the pan without breaking the wires is _________ kg (Use g = 10 m s$$^{-2}$$)