Uniform MLE II

Suppose that $X_1\mid \theta, \dots, X_n \mid \theta \sim \text{Unif}[-\theta,\theta]$ IID. If it exists, find the MLE of $\theta$ with the dataset $\{1,2,3,-4,2\}$. If it doesn't, report $-1$.

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NOTE: It may be helpful to solve Uniform MLE I before attempting this question.