numerical scheme's conservation over time

Question

Consider a conservative scheme $$ u_{j}^{n+1}=u_{j}^{n}-\frac{\Delta t}{\Delta x}\left[g\left(u_{j+\frac{1}{2}}^{L}, u_{j+\frac{1}{2}}^{R}\right)-g\left(u_{j-\frac{1}{2}}^{L}, u_{j-\frac{1}{2}}^{R}\right)\right] $$ for solving the initial value problem $$ u_{t}+f(u)_{x}=0 $$ where $g(,)$ is a numerical flux function. How can we show that the total $u(x, t)$ of the numerical solution is conserved over time.