Well, for the male, we either have a color block or we have normal vision. And that's exactly what this information tells us. So this right over here is normal. So x uppercase by, and these two are basically colorblind. So x lowercase b y and x lowercase by. So we see that by making the assumption that our trait, in this case, it's our colorblind trait, by making the assumption it's sex link recessive, we are able to basically use the information given to us in the pedigree.