So we essentially take this DNA molecule, the single strand, and we mix it with these four components. So we have the radioactively labeled DNA primer that is complementary to the three end. We have the four types of deoxy nucleuside triphosphates. These four ones shown here, we have the DNA polymerase, and we have a very small amount. So let's say about 1% of the Ddatp. So that's the specific Ddntp that we're going to choose for this specific experiment, for that specific beaker.