In the equation \(AX = B,\;A = \left[ {\begin{array}{*{20}{c}} {\frac{1}{{\sqrt 2 }}}&0&{\frac{1}{{\sqrt 2 }}}\\ 0&1&0\\ {\frac{1}{{\sqrt 2 }}}&0&{\frac{{ - 1}}{{\sqrt 2 }}} \end{array}} \right],\;X = \left[ {\begin{array}{*{20}{c}} x\\ y\\ z \end{array}} \right],B = \left[ {\begin{array}{*{20}{c}} 0\\ 1\\ { - \sqrt 2 } \end{array}} \right]\), where A is an orthogonal matrix, the sum of the unknowns, x + y + z = _______