Statistical Inference — sufficient statistic for a power distribution parameter

Let $x_1, x_2, x_3, …, x_n$ denote a random sample from a distribution with pdf $f(x; \theta) = \begin{cases}\theta x^{\theta - 1}, & 0 < x < 1 \ 0, & \text{elsewhere}\end{cases}$, where $\theta > 0$. The sufficient statistic for $\theta$ is