A company manufactures three products. The following information is obtained in respect of next month's budgeted production. For product X: contribution per unit $7, contribution per kilo $3, kilos of material required for production 400. For product Y: contribution per unit $6, contribution per kilo $4, kilos of material required for production 600. For product Z: contribution per unit $8, contribution per kilo $6, kilos of material required for production 1000. The company has been advised that only 1800 kilos of material will be available for production next month. What is the maximum contribution the company can earn?