A $20$ $\text{MVA}$, $11.2$ $\text{kV}$, $4$-pole, $50$ $\text{Hz}$ alternator has an inertia constant of $15$ $\text{MJ/MVA}$. If the input and output powers of the alternator are $15$ $\text{MW}$ and $10$ $\text{MW}$, respectively, the angular acceleration in mechanical degree/$s^{2}$ is _____________.(round off to nearest integer)