Detailed Instructions: 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.
Q: finally they had to roam around 169 factories to make sure they are throwing their wastes properly . if their group went to 69 factories and the second went to 52 how many factories remain unchecked ?
A:
48