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

Ex Input:
Problem: a car salesman earns a base salary of $ 1000 per month plus a commission of $ 200 for each car he sells . if the car salesman earned $ 2000 in march , how many cars does he need to sell in april in order to double his march earnings ?

Ex Output:
15

Ex Input:
Problem: the sum of all the digits of the integers from 18 to 21 inclusive is 24 ( 1 + 8 + 1 + 9 + 2 + 0 + 2 + 1 = 24 ) . what is the sum e of all the digits of the integers from 0 to 99 inclusive ?

Ex Output:
900

Ex Input:
Problem: how many zeroes are there at the end of the number n , if n = 100 ! + 200 ! ?

Ex Output:
2