and you compute what's called a maximum matching now what you have to provide is a loss function so we can there's a loss function L and L will take two of these things L will take the read the predicted thing of your model and L will take the true under one of the true underlying things and L will compute a number and we'll say how well do these two agree so you can say for example if either of them is the nothing class then I have no loss like I don't care about them that gives you no loss but if the two if the two classes agree and the two