Size of composite hypothesis test

Let $X_1, X_2$ be a random sample from a $U(0, \theta)$ distribution, where $\theta > 0$ is an unknown parameter. For testing the null hypothesis $H_0: \theta\in (0, 1]\cup [2, \infty)$ against $H_1: \theta\in (1, 2)$, consider the critical region $$R=\left\{(x_1, x_2)\in\mathbb{R}\times\mathbb{R} : \frac{5}{4} < \max\{x_1, x_2\} < \frac{7}{4}\right\}.$$ Then, the size of the critical region equals __________