They often are, but I'm gonna show you unequal subdivisions just to show you that this is still a valid Riemann sum. And once again, this is an overestimate where the actual area that we're trying to approximate is smaller than the area of this rectangle. And then let's say this third subdivision right over here starts right over there at x equals three. And we use the left end of the subdivision, the value of the function there to define the height of the rectangle. And once again, you see it is an overestimate. So the left Riemann sum is clearly an overestimate. And it's pretty clear why.