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

Ex Input:
Problem: joan took out a mortgage from hel local bank . each monthly mortgage payment she makes must be triple the amount of the previous month ' s payment . if her first payment is $ 100 , and the total amount she must pay back is $ 914800 , how many months will it take joan to pay back her mortgage ?

Ex Output:
9


Ex Input:
Problem: how many numbers between 200 and 600 are divisible by 4 , 5 and 6 ?

Ex Output:
6


Ex Input:
Problem: the diagonals of a rhombus are 15 cm and 20 cm . find its area ?

Ex Output:

150