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 cycle is bought for rs . 900 and sold for rs . 1170 , find the gain percent ?

Ex Output:
30 %


Ex Input:
Problem: if n is the product of all the integers from 5 to 20 , inclusive , what is the greatest integer k for which 2 ^ k is a factor of n ?

Ex Output:

1