Let $f(x) = x^{2}-4x$. To prove that $\displaystyle \lim_{x \to 2} f(x) = -4$, we proceed as follows. Given any $\epsilon > 0$, we need to find a number $\delta > 0$ such that if $0 < |x - 2| < \delta$, then $|(x^2 - 4 x) - (-4)| < \epsilon$. What is the (largest) choice of $\delta$ that is certain to work? (Your answer will involve $\epsilon$. When entering your answer, type e in place of $\epsilon$.)

$\delta$ =