Danielle is a manager at a restaurant. The employees bring to her notice that they are dissatisfied with their jobs; they feel they are not paid enough for the number of hours they work. They demand a 20 percent increase in their salaries and a two-hour reduction in their working hours. After several rounds of negotiations, both Danielle and her employees agree on a 15 percent salary hike and a reduction of one hour in their working hours. The concept of _____ is illustrated in this scenario.