Matrices & Systems · Medium problem

Let $A = \begin{pmatrix}1 & 2 & 3 \\ 4 & 1 & -3\end{pmatrix}$ and $B = \begin{pmatrix}1 & 1 \\ -1 & -2 \\ 1 & 1\end{pmatrix}$. Find the entry in row $1$, column $2$ of $AB$.