So if we multiply this ratio top and bottom by some number, we're not going to change the value of it. So let's multiply top and bottom by Avogadro's number. So remember, Avogadro's number is given by uppercase NA, and this gives us Avogadro's number of molecules. So basically 6.2 times ten to 23 molecules, this is Avogadro's number. So if you multiply top and bottom by Avogadjo's number, we won't change our result. And we get an A multiplied by m multiplied by one minus v bar, the density divided by an a multiplied by F. So this doesn't change because we can simply cross this out and we get back our result.