So this is, let's say, the nth amino acid in our sequence. This is the n plus one amino acid. This is the n plus two amino acid. This is the n plus three amino acid, and so forth. Now, to actually stabilize the beta turn and to make sure that it is stabilized and exists for an extended period of time, we have to have a bond that forms between the co group. So, wow, this is an h, not an n. So if we examine the nth amino acid, the co group of the nth amino acid interacts with the NH group of the n plus three amino acid.