27. Consider a function \(f: R \to R\) such that \(f(x) = \begin{cases} \sin(\pi x), & \text{if } x \in \mathbb{Q} \\ \tan(\pi\sqrt{|x|}), & \text{if } x \notin \mathbb{Q} \end{cases}\). If \(\displaystyle\lim_{x \to N} f(x)\) exists, then the sum of all positive integers \(N < 100\), is equal to: