Air at an initial temperature and pressure of 15 °C and 1 bar is heated in an irreversible process. The final temperature and pressure are 303 °C and 2 bar, respectively. Take gas constant $R = 287$ J/kg·K, $\gamma = 1.4$, and treat air as a calorically perfect gas. The change of entropy (in J/kg·K) in the process is \(\underline{\hspace{1cm}}\). [round off to nearest integer]