Emma decides to buy some groceries. She buys a loaf of bread for $2.50, a gallon of milk for $3.80, a dozen eggs for $2.20, and a bag of apples for $4.50. She also uses a coupon that gives her a 10% discount on the total price of the groceries. How much does Emma pay after using the coupon? Let's think step by step and output the final answer within \boxed{}.
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