And so let's suppose we want to add a bunch of deoxyguanosine triphosphates so Dgtps. And so after step four, we essentially add a polygtail to the three prime of this complementary DNA molecule. And now we know exactly what the sequence on the three prime end here is. And so just like in diagram one, where we knew exactly what the sequence was and so we knew what type of sequence to build on that DNA primer. Now we also know what sequence that DNA primer should have. If this is a polygtail, we have to build a polyceetail.