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

Ex Input:
Problem: how many diagonals does a polygon with 13 sides have , if one of its vertices does not connect to any diagonal ?

Ex Output:
54


Ex Input:
Problem: 10 ^ ( 600 ) ã · 10 ^ ( 580 ) = ?

Ex Output:
10 ^ 20


Ex Input:
Problem: two pipes a and b can separately fill a tank in 12 and 15 minutes respectively . a third pipe c can drain off 42 liters of water per minute . if all the pipes are opened , the tank can be filled in 15 minutes . what is the capacity of the tank ?

Ex Output:

504