If you knew these two data points, you could figure out that. If you knew this data point, you knew the total. You could figure out that. If you knew this data point and you knew the total, you could figure out that. And if you figured out that and that, then you could figure out this right over here. And so that's why this rule of thumb works. The number of rows minus one times the number of columns minus one gives you your degrees of freedom.