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.

Input: Consider Input: Luke was helping the cafeteria workers pick up lunch trays , but he could only carry 4 trays at a time . If he had to pick up 20 trays from one table and 16 trays from another , how many trips will he make ?

Output: 9

Input: Consider Input: Isabella ' s hair is 18 cubes long . If her hair grows 4 more inches , how long will it be ?

Output: 22

Input: Consider Input: For the school bake sale Amy made pastries . She baked 15 cupcakes and 48 cookies . After the sale she had 12 to take back home . How many pastries did she sell ?
Output: 51