Chemical Equilibrium

For the given hypothetical reactions, the equilibrium constants are as follows : $$\begin{aligned} & \mathrm{X} \rightleftharpoons \mathrm{Y} ; \mathrm{K}_1=1.0 \\ & \mathrm{Y} \rightleftharpoons \mathrm{Z} ; \mathrm{K}_2=2.0 \\ & \mathrm{Z} \rightleftharpoons \mathrm{W} ; \mathrm{K}_3=4.0 \end{aligned}$$ The equilibrium constant for the reaction $$\mathrm{X} \rightleftharpoons \mathrm{W}$$ is