For the following reaction, the equilibrium constant $$K_$$ at 298 K is $$1.6 \times 10^{17}$$
$$Fe^{2+} (aq) + S^{2-} (aq) \rightleftharpoons FeS (s)$$
When equal volumes of 0.06 M $$Fe^{2+}$$ (aq) and $$0.2 M S^{2-}(aq)$$ solutions are mixed, the equilibrium concentration of $$Fe^{2+}$$ (aq) is found to be $$Y \times 10^{-17} M$$. The value of Y is _________ .