A glass flask of $100\ \text{cm}^3$ is filled to the brim with mercury and heated by $50\ \text{K}$. How much mercury spills? ($\gamma$ of mercury $1.8 \times 10^{-4}\ \text{K}^{-1}$; $\alpha$ of glass $0.9 \times 10^{-5}\ \text{K}^{-1}$.)