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

Example Input: Problem: of the seven - digit positive integers that have no digits equal to zero , how many have two digits that are equal to each other and the remaining digit different from the other two ?
Example Output: 152409600

Example Input: Problem: 1370 , x , 1070 , - 180 , - 6430
Example Output: 1320

Example Input: Problem: if a ( a + 2 ) = 48 and b ( b + 2 ) = 48 , where a ≠ b , then a + b =
Example Output:
- 9