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.

Example Input: there are 12 birds on the fence . 8 more birds land on the fence . how many birds are on the fence ?
Example Output: 20

Example Input: the library has 75 science books . the second graders borrowed 18 of them . what 's the difference between the number of science books the library has in the beginning and the second graders borrowed ?
Example Output: 57

Example Input: kelly has 121 nintendo games . how many does she need to give away so that she will have 22 games left ?
Example Output:
99

