Frobenius & Special Functions · Easy problem

Bessel's equation of order $\tfrac13$, $x^2y'' + xy' + \left(x^2 - \tfrac19\right)y = 0$, has a regular singular point at $x = 0$. Compute the difference $r_1 - r_2$ between the larger and smaller indicial roots. Express your answer as a common fraction.