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

Example input: Maria has 3 boxes of eggs . Each box holds 7 eggs and there are 8 boxes in a case . How many eggs does Maria have ?
Example output: 21
Example explanation: Total number of eggs that Maria has is 3*7 = 21
Q: Bianca was organizing her book case making sure each of the shelves had exactly 8 books on it . If she had 5 shelves of mystery books and 4 shelves of picture books , how many books did she have total ?
A:
72