4. Let $A=\{(\alpha, \beta, \gamma) \mid \alpha+\beta \sin x+\gamma \cos x=0, x \in(-\infty,+\infty)\}$, then the number of elements in the set $A$ is $m=$
$\qquad$ .
Take $x=0, \frac{\pi}{2}, \pi$, we have $\left\{\begin{array}{l}\alpha+\gamma=0, \\ \alpha+\beta=0, \\ \alpha-\gamma=0\end{array} \Rightarrow\left\{\begin{array}{l}\alpha=0, \\ \beta=0, \\ \gamma=0 .\end{array}\right.\right.$ Therefore, $m=1$.