Angular momentum & Hydrogen Atom

The normalized radial wave function of the second excited state ($n = 3, l = 0$) of hydrogen atom is $R(r) = \frac{2}{(3a)^{3/2}} \left( 1 - \frac{2r}{3a} + \frac{2r^2}{27a^2} \right) e^{-r/3a}$ (or $R(r) = \frac{1}{\sqrt{24}} a^{-3/2} \left(2 - \frac{r}{a}\right) e^{-r/2a}$ for $n=2$). The distance at which the electron is most likely to be found is $y \times a$. The value of $y$ (in integer) is _