During thin-layer drying of corn grain falling within the falling rate period following Newton's law of drying $\frac{M - M_e}{M_0 - M_e} = e^{-k t}$, the initial moisture is $M_0 = 24\%$, equilibrium moisture is $M_e = 10\%$, and the drying constant is $k = 0.35\text{ h}^{-1}$. Calculate the drying time in $\text{hours}$ required to reduce the moisture content to $13.5\%$. (All moistures dry basis)