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

Ex Input:
Problem: a and b can together finish a work in 40 days . they worked together for 10 days and then b left . after another 15 days , a finished the remaining work . in how many days a alone can finish the job ?

Ex Output:
2


Ex Input:
Problem: a can do a work in 15 days and b in 20 days . if they work on it together for 7 days , then the fraction of the work that is left is

Ex Output:
11 / 6


Ex Input:
Problem: what is the total surface area in square meters of a rectangular solid whose length is 9 meters , width is 8 meters , and depth is 5 meters ?

Ex Output:

314 m