Pure rolling-1!

Classical Mechanics Level 4

A uniform disc of mass $m$ and radius $R$ is projected horizontally with velocity $v_0$ on a rough horizontal floor so that it starts off with a purely sliding motion at $t = 0$ . After $\large t_0 = \frac{v_0}{nμg}$ second, it acquires a purely rolling motion. Find the value of $n$ .