Functions

Let \(f: R-\left\{\frac{-1}{2}\right\} \rightarrow R\) be defined by \(f(x)=\frac{x-2}{2 x+1}\). If \(\alpha\) and \(\beta\) satisfy the equation \(f(f(x))=-x\), then \(4\left(\alpha^2+\beta^2\right)=\)