So let's suppose we have the following three nucleotide nucleic acid. So since we're dealing with our deoxyribosugar, this is a DNA molecule. Now, the direction that we write our DNA molecule in is beginning at the five prime end and ending at the three prime end. So to see what we mean by that, let's label our carbon. So this is carbon prime one. So one prime, two prime, three prime, four prime and five prime.