The task is to generate the correct answer for a given math problem.

Ex Input:
Problem: a car traveled 560 miles per tankful of gasoline on the highway and 336 miles per tankful of gasoline in the city . if the car traveled 6 fewer miles per gallon in the city than on the highway , how many miles per gallon did the car travel in the city ?

Ex Output:
9


Ex Input:
Problem: if 1.5 cm of a pencil is purple , 0.5 cm of the remaining is black and the remaining 2 cm is blue , what is the total length of the pencil ?

Ex Output:
4 cm


Ex Input:
Problem: solve for x and check : - 12 x = 72

Ex Output:

- 6