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

[EX Q]: A store had 86 coloring books in stock . They ended up putting them on sale and getting rid of 37 of them . The put the ones they still had onto shelves with 7 on each shelf . How many shelves did they use ?
[EX A]: 7

[EX Q]: Tiffany baked 8 brownies , but needed 17 total for her party . If she used 8 cups of flour on each one , how much cups of flour does she still need ?
[EX A]: 72

[EX Q]: Mark 's father gave him $ 85 . Mark bought 10 books , each of which cost $ 5 . How much money does Mark have left ?
[EX A]:
35