$\mathrm{A}(g) \rightleftharpoons 2 \mathrm{~B}(g)+\mathrm{C}(g)$

For the given reaction, if the initial pressure is $450 \mathrm{~mm} ~\mathrm{Hg}$ and the pressure at time $\mathrm{t}$ is $720 \mathrm{~mm} ~\mathrm{Hg}$ at a constant temperature $\mathrm{T}$ and constant volume $\mathrm{V}$. The fraction of $\mathrm{A}(\mathrm{g})$ decomposed under these conditions is $x \times 10^{-1}$. The value of $x$ is ___________ (nearest integer)