$$\begin{gathered} \left[\mathrm{A}\right] \to \left[\mathrm{B}\right] \\ \mathrm{Reactant} \mathrm{Product} \end{gathered}$$

If formation of compound [B] follows the first order of kinetics and after 70 minutes the concentration of [A] was found to be half of its initial concentration. Then the rate constant of the reaction is x × 10^—6 s^—1 . The value of x is______. (Nearest Integer)