3. Let $\tan \alpha$ and $\tan \beta$ be two solutions of the equation $x^{2}-3 x-3=0$. Find the value of
$$
\left|\sin ^{2}(\alpha+\beta)-3 \sin (\alpha+\beta) \cos (\alpha+\beta)-3 \cos ^{2}(\alpha+\beta)\right| .
$$
(Note: $|x|$ denotes the absolute value of $x$.)