Two identical blocks of ice move in opposite directions with equal speed and collide with each other. What will be the minimum speed required to make both the blocks melt completely, if the initial temperatures of the blocks were $-8^\circ\text{C}$ each? (Specific heat of ice is $2100\ \text{Jkg}^{-1}\text{K}^{-1}$ and latent heat of fusion of ice is $3.36 \times 10^5\ \text{Jkg}^{-1}$)