4. Let $\alpha, \beta, \gamma \in \mathbf{R}$, and satisfy
$$
\begin{array}{l}
\sin \alpha \cdot \cos \beta+|\cos \alpha \cdot \sin \beta| \\
\quad=\sin \alpha \cdot|\cos \alpha|+|\sin \alpha| \cdot \cos \beta .
\end{array}
$$

Then the minimum value of $(\tan \gamma-\sin \alpha)^{2}+(\cot \gamma-\cos \beta)^{2}$ is