Vector Calculus · Challenge problem

Let $\mathbf F = (yz + y,\; xz,\; xy)$ and let $C$ be the helical arc $\mathbf r(t) = \left(\cos t,\; \sin t,\; \dfrac{4t}{\pi}\right)$, $0\le t\le\dfrac{\pi}{4}$. Evaluate $\displaystyle\int_C\mathbf F\cdot d\mathbf r$.