So it really turns into a game. So you tell me how close you want. So this is the game. You tell me how close you want f of x to be to l. And you do this by giving me a positive number that we call epsilon, which is really how close you want f of x to be to l. So you give a positive number epsilon. And epsilon is how close do you want to be. How close. So for example, if epsilon is 0.01, that says that you want f of x to be within 0.01 of epsilon.