And this is essentially step A. So in Step A, we expose the original homogeneous mixture to the SDS Page setup and we get the following distribution of bands. So this is step A, and for step A, these are the different types of bands. And each band basically represents a type of protein with a specific type of size, with a specific type of mass. So remember, in SDS polyacryla my gel electrophoresis, the proteins that have a higher mass are higher up, but the proteins that are smaller have a lower mass, lower size, are lower along our gel. Now, in Step A, we basically find that the total protein in milligrams that we're dealing with is 20,000 milligrams.