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

Example Input: Problem: how many prime numbers are between 51 / 13 and 89 / 9 ?
Example Output: 2

Example Input: Problem: a sum of money at simple interest amounts to rs . 815 in 3 years and to rs . 878 in 4 years . the sum is :
Example Output: 626

Example Input: Problem: what is remainder of the division ( 1625 * 1627 * 1629 ) / 12 ?
Example Output:
3