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

Ex Input:
Problem: 1370 , x , 1070 , - 180 , - 6430

Ex Output:
1320


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: ajay can ride 50 km in 1 hour . in how many hours he can ride 1500 km ?

Ex Output:

30 hrs