Maximum likelihood estimate of the square of a location parameter

Let $x_1=1.1$, $x_2=0.5$, $x_3=1.4$, $x_4=1.2$ be the observed values of a random sample of size four from a distribution with the probability density function

$$f(x|\theta)=\begin{cases}e^{\theta-x}, & x\ge\theta,\ 0, & \text{otherwise,}\end{cases}\quad\theta\in(-\infty,\infty).$$

Then the maximum likelihood estimate of $\theta^2$ is