Let the mean and the standard deviation of the probability distribution $$\begin{array}{|c|c|c|c|c|} \hline X & \alpha & 1 & 0 & -3 \\ \hline P(X) & \frac{1}{3} & K & \frac{1}{6} & \frac{1}{4} \\ \hline \end{array}$$ be $$\mu$$ and $$\sigma$$, respectively. If $$\sigma - \mu = 2$$, then $$\sigma + \mu$$ is equal to ________