 But when you put the furin cleavage site, it no longer can attach to the bat receptor well. But now it can attach to the human receptor. And it's very interesting. If you study that carefully, it's basically 12 nucleotides that they put in there. And it's important, as another observation, is that those nucleotides, three of them code for an amino acid. So if you have 12, you have four amino acids. The nucleotide sequence that's used with the