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

Example Input: Context: Marco and his dad went strawberry picking. Together their strawberries weighed 20 pounds. His dad's strawberries weighed 17 pounds. 

 Question: How much did marco's strawberries weigh?
Example Output: 3

Example Input: Context: Mary is baking a cake. The recipe calls for 14 cups of flour and 6 cups of sugar. She already put in 5 cups of flour. 

 Question: How many more cups of flour than cups of sugar does she need to add now?
Example Output: 3

Example Input: Context: There are 16 different books and 14 different movies in the ' crazy silly school ' series. If you read 19 of the books and watched 13 of the movies 

 Question: How many more books than movies are there in the ' crazy silly school ' series?
Example Output:
2