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

Example Input: Problem: find the least number must be subtracted from 62575 so that remaining number is divisible by 99 .
Example Output: 7

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 15 km / hr . for how many minutes does the bus stop per hour ?
Example Output: 4

Example Input: Problem: a ladder 22 feet long is leaning against a wall that is perpendicular to level ground . the bottom of the ladder is 7 feet from the base of the wall . if the top of the ladder slips down 3 feet , how many feet will the bottom of the ladder slip ?
Example Output:
12.86