Triple Integrals & Coordinate Systems · Hard problem

Evaluate $\displaystyle\int_0^1\int_0^{\pi/2}\int_y^{\pi/2}\dfrac{\sin z}{z}\,dz\,dy\,dx$. (The inner integral over $z$ cannot be done first, since $\sin z/z$ has no elementary antiderivative – reverse the order of the two inner integrals instead.)