how do i solve a problem like this?

What is the net charge of the oligopeptide Ala-Glu-Asn-Leu-Lys at pH 12? \begin{tabular}{|c|} \hline2 \\ \hline1 \\ \hline 0 \\ \hline+1 \\ \hline+2 \\ \hline \end{tabular}