So X-B-Y-X-B-Y. So from this information, what this tells us is every single individual produced in this case must carry that particular phenotype for that disease. And we know that is not consistent with the information that is given to us because these two individuals don't carry that particular phenotype as described by this pun and square. So we know it cannot be this genotype here. So, okay, now we know that. Let's continue into the next one.