You will be given a definition of a task first, then some input of the task.
You are given a math word problem and you are supposed to apply multiple mathematical operators like addition, subtraction, multiplication, or division on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

a mirror store has 78 mirrors in stock . 8 mirrors are broken and 57 mirrors are sold . how many mirrors are left ?
Output:
13