$\begin{array}{ccc} [A] & \longrightarrow & [B] \\ \text{(Reactant)} & & \text{(Product)} \end{array}$

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