And it's very clear here that this is going to be an underestimate, underestimate, because we see in each of these intervals, the Riemann, the right Riemann sum, or the rectangle that we're using for the right Riemann sum is a subset of the area that it's trying to estimate. We're not able to, it doesn't capture this extra area right over here. And once again, that is because this is a strictly decreasing function. So if you use the right endpoint of any one of these, or the right side of any of these subdivisions in order to define the height, that right value of g is going to be the lowest value of g in that subdivision. And so it's going to be a lower height than what you could even say is the average height of the value of the function over that interval. So you're going to have an underestimate in this situation. Now, if your function was strictly increasing, then these two things would be swapped around.