Matrices & Systems · Medium problem

Let $A = \begin{pmatrix}-1 & -3 & 0 \\ 2 & -1 & 1\end{pmatrix}$ and $B = \begin{pmatrix}1 & -2 \\ 3 & 1 \\ -1 & -3\end{pmatrix}$. Find the entry in row $2$, column $1$ of $AB$.