[ A ] → [ B ] Reactant Product If formation of compound [B] follows the first order of kinetics and after 70 minutes the concentration of [A] was…

$\displaystyle [\mathrm{A}] \quad \rightarrow \quad[\mathrm{B}]$ Reactant Product If formation of compound [B] follows the first order of kinetics and after $\displaystyle 70$ minutes the concentration of [A] was found to be half of its initial concentration. Then the rate constant of the reaction is $\displaystyle x \times 10^{-6} \mathrm{~s}^{-1}$. The value of $\displaystyle x$ is \_\_\_\_. (Nearest Integer)