Budget Auto produces inexpensive cars. Each car is sold for US$7,900. The raw material in a car costs US$5,000. Both labor time and robot time are needed to produce cars, i.e. they are not substitutes to each other. A worker can do the needed labor on, at most, 100 cars per month; a robot can complete the needed work on, at most, 200 cars per month. The company currently has 4 workers. Each worker receives a monthly salary of US$6,000. It costs US$2,500 to hire a worker and US$1,000 to fire a worker. Hired workers are fully productive during the month they are hired. Robots must be bought at the beginning of month 1 at a cost of US$15,000 per robot, and there is no variable cost for robots during the production process. The demand for car is listed in the data file. At the end of each month, the company incurs a holding cost of US$200 per car.

What is the maximum profit that the company can earn during the next six month?