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

Example Input: Problem: evaluate : 96385 + 12 * 3 * 25 = ?
Example Output: 96485

Example Input: Problem: a man whose speed is 4.5 kmph in still water rows to a certain upstream point and back to the starting point in a river which flows at 1.5 kmph , find his average speed for the total journey ?
Example Output: 4

Example Input: Problem: a certain debt will be paid in 65 installments from january 1 to december 31 of a certain year . each of the first 20 payments is to be $ 410 ; each of the remaining payments is to be $ 65 more than each of the first 20 payments . what is the average ( arithmetic mean ) payment that will be made on the debt for the year ?
Example Output:
455