And what we want to do is have three equal subdivisions. And there's three very natural subdivisions here. If we make each of our subdivisions three wide, so this could be a subdivision. And then this is another subdivision. And when you do Riemann sums, you don't have to have equal subdivisions, although that's what you'll often see. So we've just divided going from one to 10 into three equal sections that are three wide. So that's three, this is three, and this is three.