A company faces the aggregate planning problem shown in the table below. Cost of regular production is $$8$ per unit, the cost of producing the same unit on overtime is $$15,$ the cost of subcontracting is $$12$ per unit, and the cost of carrying a unit in inventory from one month to the next is $$6.$ January February March April May Forecast $4008001200700300$ Beginning Inventory $100$ The labor contract at the plant prohibits both overtime and subcontracting output to exceed $400$ units in any five month window. The plant capacity is $20$ units per day produced using two shifts and the plant runs seven days a week. By policy, management wants to avoid stockouts. Formulate the aggregate plan using linear programming and solve it using Solver. What's the total cost of the aggregate plan?