Let \( f(x) = \left| 2x^2 + 5|x| - 3 \right| ,\; x \in \mathbb{R} \). If \( m \) and \( n \) denote the number of points where \( f \) is not continuous and not differentiable respectively, then \( m + n \) is equal to:
\( 5 \)
\( 2 \)
\( 0 \)
\( 3 \)