The amount of biomass in a reactor at the end of the batch process is $50 \; \text{g}.$ Fed-batch operation is initiated by feeding the substrate solution at a constant rate of $1 \; \text{L h}^{-1}.$ The concentration of substrate in the feed is $50 \; \text{g L}^{-1}.$ The maximum biomass yield $(Y_{XS}^{M})$ is $0.4 \frac{\text{g biomass}}{\text{g substrate}}.$ Assuming the system is at quasi-steady state, the maximum amount of biomass after $5 \; \text{h}$ of feeding is __________ $\text{g}.$