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

Ex Input:
Problem: a is half good a work man as b and together they finish a job in 14 days . in how many days working alone b finish the job ?

Ex Output:
21


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: the difference between the value of a number increased by 12.5 % and the value of the original number decreased by 25 % is 30 . what is the original number e ?

Ex Output:

80