A loamy soil with the dry unit weight of 1.3 g/cc has the root zone depth of 80 cm. The field capacity is 30 percent and the plant start wilting if the moisture content falls below 10 percent. If it is given that the minimum water depth required for the optimum growth of the plant is the half of the field capacity moisture, then the water required to raise the water level from wilting point to optimum moisture is ______