The pole $$-$$ zero configuration of a phase lead compensator is given by

The matrix of any state space equations for the transfer function $$C(s)/R(s)$$ of the system, shown below in. Figure is

The closed loop system , of Figure, is stable if the transfer function $$T\left( s \right) = {{C\left( s \right)} \over {R\left( s \right)}}$$ is stable.

The number of positive real roots of the equation $${s^3} - 2s + 2 = 0$$ is __________.