Vector Algebra

$3 \hat{\mathbf{i}}-2 \hat{\mathbf{j}}-\hat{\mathbf{k}},-2 \hat{\mathbf{i}}-\hat{\mathbf{j}}+3 \hat{\mathbf{k}}$ and $-\hat{\mathbf{i}}+3 \hat{\mathbf{j}}-2 \hat{\mathbf{k}}$ are the position vectors of the vertices $A, B$ and $C$ of a $\triangle A B C$ respectively. If $H$ is its orthocentre, then $\mathbf{H A}+\mathbf{H B}+\mathbf{H C}=$