We take, for each of the days, we take the difference between the observed and the expected. So it's going to be 30 minus 20. I'll do the first one color-coded. Squared divided by the expected. So we're essentially taking the square of, almost you could kind of view it, the error between what we observed and expected, or the difference between what we observed and expected. And we're kind of normalizing it by the expected right over here. But we want to take the sum of all of these.