Suppose that you enter into a long contract to buy July silver for $17.86 per ounce on NYMEX. The size of the contract is 5000 ounces. The initial margin is $4,130 per contract, and the maintenance margin is $3,143 per contract. At what price are you going to receive a margin call? Please keep two decimal points and write your answer in dollars (e.g. 15.61). Please do not write dollar sign in your answer.