On July 1, an investor holds 50,000 shares of a certain stock. The market price is $72 per share. The investor is interested in hedging against movements in the market over the next month and decides to use the September S&P 500 futures contract. The index futures price is 2,160 and one contract is for delivery of $50 times the index. The beta of the stock is 1.3. How many futures contracts should the investor enter (after rounding to the nearest contract)? (enter positive number for long contracts and negative number for short contracts)