Well, the answer is simple. Just like many processes in nature, the Edmund degradation is not a perfect process and sometimes it does make a mistake, it does create an error. So it turns out that the Edmund degradation process in some cases does not release that amino acid, the first amino acid in that polypeptide chain. Now to demonstrate how this can be a problem, to demonstrate how this affects accuracy of our procedure, suppose that the efficiency of a single admin degradation process is 97% and that's a high value. So what that means is every time the Edmund degradation process takes place, there's a 97% chance that the process will take place correctly. We will label that initial amino acid and then release that amino acid.