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

Ex Input:
Problem: if a - b = 6 and a 2 + b 2 = 50 , find the value of ab .

Ex Output:
a ) 7

Ex Input:
Problem: the smallest value of n , for which n + 2 is not a prime number , is

Ex Output:
2,4

Ex Input:
Problem: on june 1 a bicycle dealer noted that the number of bicycles in stock had decreased by 3 for each of the past 5 months . if the stock continues to decrease at the same rate for the rest of the year , how many fewer bicycles will be in stock on september 1 than were in stock on january 1 ?

Ex Output:
24