Given the task definition and input, reply with output. Given a math word problem, answer the following question. You might need to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the question and then only report the final numerical answer.

mrs. hilt made 5 rice krispie treats . she used 8 large marshmallows and 10 mini marshmallows . how many marshmallows did she use altogether ?
18