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

Example Input: Charles has 25 Skittles . Diana takes 7 away . How many Skittles will Charles have ?
Example Output: 18

Example Input: Gary had 73 dollars . He spent 55 dollars on a pet snake . How many dollars did Gary have left ?
Example Output: 18

Example Input: Randy has 78 blocks . He uses 19 blocks to build a tower . How many blocks are left ?
Example Output:
59