You are given a math word problem and you are supposed to apply a single mathematical operators like addition, subtraction, multiplication or division on the numbers embedded in the text to answer the following question and then only report final the numerical answer.

Ex Input:
If your gross pay is 450 dollars , while your net pay is 315 dollars , how much do you pay in taxes ? Assume that all tax dollars are not included in net pay .

Ex Output:
135


Ex Input:
Keith has 20 books . Jason has 21 books . How many books do they have together ?

Ex Output:
41


Ex Input:
Juan ran 80 miles at 10 miles per hour . How long did Juan run ?

Ex Output:

8