Least square in two dimensions.

Question

Let $A = \begin{pmatrix} 1 & 1\\ 1 & 1\\ \end{pmatrix}$ and $B = \begin{pmatrix} 2 & 3\\ 3 & 2\\ \end{pmatrix}$. Then we have to find $X \in M_{2 \times 2}$ such that $||AX - B||$ is minimized over all $X$. This looks like least square in two dimensions. I have no idea how to proceed with the problem!!