And so what that means is we not only use one ATP in this step, but we actually use two equivalent ATP molecules because the hydrolysis of Pyrophosphate basically is equivalent to hydrolyzing a single ATP molecule. And so here we actually use two and not one ATP molecules. So once we form Argine succinate, that is then used in step four. And so now what we want to use is we want to basically transform or remove the carbon skeleton that came from Aspartate. So we want to keep this nitrogen group shown here on this structure. But we want to remove this carbon skeleton and recycle that carbon skeleton.