Two blocks $A$ and $B$, each of mass $m$ are connected by means of a pulley-spring system on a smooth inclined plane of inclination $\theta$ as shown in Fig $9.45$. All the pulleys and spring are ideal. Now, $B$ is slightly displaced from its equilibrium position. It starts to oscillate. Time period of oscillation of $B$ will be $T=2 \pi \sqrt{\frac{5 m}{n k}}$, then the value of $n$ is.