For a chemical reaction $\mathrm{A}+\mathrm{B} \rightleftharpoons \mathrm{C}+\mathrm{D}\left(\Delta_{\mathrm{r}} \mathrm{H}^0=\right. 80 \mathrm{~kJ} \mathrm{~mol}^{-1}$ ) the entropy change $\Delta_{\mathrm{r}} \mathrm{S}^0$ depends on the temperature T (in K ) as ( $\Delta_{\mathrm{r}} \mathrm{S}^0=2 \mathrm{~T}\left(\mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$ ) Minimum temperature at which it will become spontaneous is $\_\_\_\_$ K. (Integer)