Vectors in Space · Easy problem

Vectors $\mathbf u$ and $\mathbf v$ have $\lVert \mathbf u \rVert = 4$ and $\lVert \mathbf v \rVert = 5$, and the angle between them is $\dfrac{\pi}{6}$. Find $\lVert \mathbf u \times \mathbf v \rVert$.