An investor shorts three December gold futures contracts at a futures price of $1837 per ounce. One contract is for 100 ounces of gold. The initial margin required is $9,000 per contract while the maintenance margin is $6,750 per contract. At the end of the first day, the futures price is $1894 per ounce. What is the TOTAL margin call for the three contracts at the end of the first day?

The answer is 17100. Please explain how to get this answer. Thank you!