Line integral of a scalar field

Question

Given the following curve $$\alpha(t)=(t-\sin(t),1-\cos(t)),\quad 0\leq t\leq\pi$$ I have to evaluate $$\oint_{\alpha}xy\,ds$$ Since $$\alpha'(t)=(1-\cos(t),\sin(t))$$ then $$\|\alpha'(t)\|=\sqrt{2-2\cos(t)}=\sqrt{2}\sqrt{1-\cos(t)}$$ So $$\oint_{\alpha}xy\,ds=\int_{0}^{\pi}\sqrt{2}(t-\sin(t))(1-\cos(t))^{3/2}\,dt$$ I thought that, if $u=t-\sin(t)\Rightarrow du=(1-\cos(t))dt$, but I don't know how to proceed with $3/2$ in the exponent.