You are given a math word problem and you are supposed to apply a single mathematical operator 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.

Example Input: katie had 9 math problems for homework . if she finished 5 of them on the bus ride home how many more did she have to do ?
Example Output: 4

Example Input: lana had 72 extra nickels . if she put them into stacks with 8 in each stack how many stacks could she make ?
Example Output: 9

Example Input: a clown had 82 balloons . after a party he had 16 left . how many balloons did he use at the party ?
Example Output:
66