sequences and series - Closed form for the finite sum $sum_{r=1}^n frac{1}{r^2}$

What will be the value of
$$\sum_{r=1}^n \frac{1}{r^2}$$

in terms of finite $n$?

I tried to solve it using $V_n$ method but couldn't get how to convert this series in telscopic series.

Please anyone help me to solve it.