complex analysis - find $lim_{zrightarrow 0}left(frac{1}{z^{2}}-frac{1}{sin^{2}z}right)$

Find $\lim_{z\rightarrow 0}\left(\frac{1}{z^{2}}-\frac{1}{\sin^{2}z}\right)$.
First I let $z=x+iy$ and then substitute to the limit and I let $y=0$ so it now limit $x\rightarrow 0$. So i use L'Hopital but I didn't get the answer.