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

Ex Input:
Problem: the population of a bacteria culture doubles every 2 minutes . approximately how many minutes will it take for the population to grow from 1,000 to 300,000 bacteria

Ex Output:
16


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

Ex Output:
2


Ex Input:
Problem: a hall is 15 meters long and 15 meters wide . if the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls , what is the volume of the hall ( in cubic meters ) ?

Ex Output:

1687.5