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

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

Example Input: Problem: if a a b = 2 a - 3 b + ab , then 3 a 2 + 2 a 3 is equal to :
Example Output: 7

Example Input: Problem: if the average of 16 x and 8 y is greater than 80 , and x is twice y , what is the least integer value of x ?
Example Output:
8