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: A restaurant served 4 pies during lunch and 9 during dinner today . The restaurant served 7 pies and 2 pizzas yesterday . How many pies were served in total ?
Example Output: 20

Example Input: Megan has 19 seashells . How many more seashells does she need to find to have 25 seashells in her collection ?
Example Output: 6

Example Input: The Litter Patrol picked up 10 glass bottles and 8 aluminum cans on Saturday . How many pieces of litter did they pick up altogether ?
Example Output:
18