And for cysteine, the group, the side chain group is we have this ch two group. And then we have the sulfur that is bound to our age. And now we finish off this peptide by drawing the terminal alpha carboxyl group. Okay, so this is our five amino acid peptide. So amino acid one, two, amino acid three, four and five. Now the next step is to basically label all the groups on the peptide that can lose or gain an age atom.