So this basically describes the entire rate of dissociation of the enzyme substrate complex. So it can dissociate not only going this way, but also going this way. And that's why we have these two summations. So we sum this with this and that gives us the rate at which our enzyme substrate complex actually breaks down. So before we actually continue now, we have to make an important assumption. And the assumption that we make is that our reaction is at a steady state condition.