For the reaction $A\left(g\right)\to B\left(g\right),$ the value of the equilibrium constant at 400K and 1atm is equal to 1000.0. The value of ${\Delta }_r{G}^0$ for the reaction at 400K and 1atm in $Jmo{l}^{-1}$ is $-xR,$ where x is _______(Rounded off to the nearest integer) $(\ln 10=2.303)$