Instructions: 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.
Input: oliver was weighing boxes for moving . the first was 2 pounds the second was 3 pounds and the last was 13 pounds . what 's the difference between the weight of the first box and the third box ?
Output:
11