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

Example Input: Problem: excluding stoppages , the average speed of a bus is 60 km / hr and including stoppages , the average speed of the bus is 40 km / hr . for how many minutes does the bus stop per hour ?
Example Output: 20 min

Example Input: Problem: the cash realised on selling a 14 % stock is rs . 106.25 , brokerage being 1 / 4 % is ?
Example Output: 106

Example Input: Problem: a and b can do a work in 5 days and 10 days respectively . a starts the work and b joins him after 2 days . in how many days can they complete the remaining work ?
Example Output:
2