So the total sum of the size of the objects that I select to be in the knapsack, so say I select this object to be in the knapsack and this one here but I don't want this one here, then that means that the total size of these two objects cannot exceed the capacity of the container and among all other possibilities of putting objects into the container without exceeding maximum capacity, this gives me the best possible value, and of course, here for the values, we again do the sum to calculate the total value. 