If the system of equations $\left.\begin{array}{l}\mathrm{x}-\mathrm{\lambda y}-\mathrm{z}=0\\ \mathrm{\lambda x}-\mathrm{y}-\mathrm{z}=0\\ \mathrm{x}+\mathrm{y}-\mathrm{z}=0\end{array}\right\}$ has a unique solution, then the range of $\mathrm{\lambda }\text{ is }\mathrm{R}-\{\mathrm{a},\mathrm{b}\}$,  Then the value of 
(a² + b²) is