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

Ex Input:
Problem: what is the greatest prime factor of 2 ^ 10 - 1 ?

Ex Output:
3


Ex Input:
Problem: if 5 % more is gained by selling an article for rs . 360 than by selling it for rs . 340 , the cost of the article is ?

Ex Output:
400


Ex Input:
Problem: what is the remainder when 54617 ^ ( 42788234 ) is divided by 5 ?

Ex Output: