And what happens is this guy cancels out and this guy becomes a five, because seven minus five is seven minus two is five. So I'm done. Step five. In step six, I want to consider the fact that energy or charge is concerned, like mass is concerned. And that means I have to whatever amount of electrons lost by one atom or by one side has to be gained by another side. So notice on this side, I have two electrons, on this side, I have five electrons.