13B-11. Can someone show me how to do this problem?

Will rate a thumb up for good response thanks so much (PLEASE CIRCLE OR HIGHLIGHT final answer thx)

Jerusalem Medical Ltd., an Israeli producer of portable kidney dialysis units and other medical products, develops a 4-month aggregate plan. Demand and capacity (in units) are forecast as follows: Month 1 Month 2 Month 3 Month 4 Capacity Source Labor Regular time Overtime Subcontract Demand 300 18 225 15 14 240 275 28 15 318 300 26 15 331 17 301 The cost of producing each dialysis unit is $875 on regular time, $1,310 on overtime, and $1,600 on a subcontract. Inventory carrying cost is $100 per unit per month. There is to be no beginning or ending inventory in stock and backorders are not permitted. Minimizing cost using the transportation method, the optimal cost is $ (enter your response as a whole number)