A sequence of real numbers $\displaystyle (u_1,u_2,u_3,...,u_n)$ has the following properties

$\displaystyle u_1= \sqrt{2}$ , $\displaystyle u_2=\pi$

$\displaystyle u_n=u_{n-1}-u_{n-2}$ for $\displaystyle n\geq{3}$

What is the value of $\displaystyle u_{2008}$?

Thanks for the help.