Ambient air flows over a heated slab having flat, top surface at $y = 0$. The local temperature (in Kelvin) profile within the thermal boundary layer is given by $\text{T(y)} = 300 + 200 \exp (-5y)$, where $\text{y}$ is the distance measured from the slab surface in meter. If the thermal conductivity of air is $1.0 \text{ W/m.K}$ and that of the slab is $100 \text{ W/m.K}$, then the magnitude of temperature gratitude $\text{|dT/dy|}$ within the slab at $y=0$ is ____________________ $\text{K/m} (\textit{round off to the nearest integer}$).