So now we have two beakers with these two different polypeptide chains. And now all we have to do in step three is do exactly what we did follow the same exact procedures that we followed with those individual polypeptide chains, as we discussed previously. So what that means is, for example, let's suppose we take that beaker number one that contains our green polypeptide chain. What we have to do is we have to expose that polypeptide chain to proteolytic molecules that cleave our peptide at specific locations. So we essentially cut up and divide this long fragment, this long polypeptide chain, into many small fragments. And then we take each one of these fragments and we run egman degradation on each one of these fragments.