For the reaction $\mathrm{A} \rightarrow \mathrm{B}$, the rate constant $\mathrm{k}\left(\right.$ in $\left.\mathrm{s}^{-1}\right)$ is given by $$ \log _{10} k=20.35-\frac{\left(2.47 \times 10^3\right)}{T} $$ The energy of activation in $\mathrm{kJ} \mathrm{mol}^{-1}$ is $\_\_\_\_$ . (Nearest integer) [Given : $\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$ ]