12. Given the set $M=\{x \mid 1 \leqslant x \leqslant 10, x \in \mathbf{N}\}$, for its non-empty subset $A$, multiply each element $k$ in $A$ by $(-1)^{k}$, and then find the sum (for example, if $A=\{1,3,6\}$, the sum can be calculated as $\left.(-1) \cdot 1+(-1)^{3} \cdot 3+(-1)^{6} \cdot 6=2\right)$, then for all non-empty subsets of $M$, the total sum of these sums is. $\qquad$.
12. Answer 2560