Given an open loop transfer function \(G\left( s \right) = \frac{1}{{\left( {s + 2} \right)\left( {s + 3} \right)}}\). A compensator \({G_c}\left( s \right) = K\frac{{s + a}}{{s + b}}\) is designed such that the closed loop poles at s = -1 ± j. The value of (K + a + b) is ______