My house occupies the rectangle [1, 1] [1, 1] in the x, y plane (measured in meters - it's a small house), and the height of the roof above the ground at position (x,y) is given (in meters) by the function

h(x,y)=3xy

The inside of the house therefor consists of all points

{(x,y,z):1x1,1y1,0zf(x,y)}

If the house were entirely filled with water from the ground to the roof, how many cubic meters of water would it hold?