Consider the case were we only use 12-hour nurses over a 4-week (28-day) horizon. In this case, we have m nurses on our roster, which we will pay regardless of assignment. We no longer have the restriction of 3-days on followed by 4-days off. Develop a formulation where our hard constraints are that we meet demand for both shifts each day and that a nurse can't work two shifts in a row. We would like to use two goals (soft constraints): i) Nurses get at least 2 weekend days off over the month, and ii) Nurses would like to work exactly 16 days over the month. Clearly define your decision variables. You only need to formulate this.