You are given a math word problem and you are supposed to apply a single mathematical operator 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.

Example Input: there are 28 students in mrs. riley 's class but she only has 19 pencils . how many more pencils does mrs. riley need ?
Example Output: 9

Example Input: there were 8 red roses and 2 white roses in the vase . melanie cut some more roses from her flower garden . there are now 14 red roses in the vase . how many red roses did she cut ?
Example Output: 6

Example Input: the exit door leads to a river 487 inches across if the bridge he needs to cross is only 295 inches how much longer does he need to build if he wants to cross the river using the bridge ?
Example Output:
192