An engine takes in 5 moles of air at $20^{\circ} \mathrm{C}$ and 1 atm , and compresses it adiabatically to $1 / 10^{\text {th }}$ of the original volume. Assuming air to be a diatomic ideal gas made up of rigid molecules, the change in its internal energy during this process comes out to be X kJ . The value of $X$ to the nearest integer is $\_\_\_\_$