So this is histidine 141 Lysine 82 and histidine two. These are the three residues that contain the positive charges found on the beta one subunits located at the center of the hemoglobin. And these are the three residues, HistoGene two Lysine 82 and HistoGene 143 that are found on the beta two subunits. So the number basically describes its position along that sequence, along the polypeptide sequence. So all these six residues contain positive charges and those positive charges form these electrostatic interactions with the negative charges on the two three BPG. And this decreases the overall net charge in this area and that stabilizes the deoxy hemoglobin and it stabilizes the T state.