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

Input: Consider Input: Problem: a contractor undertook to do a piece of work in 18 days . he employed certain number of laboures but 9 of them were absent from the very first day and the rest could finish the work in only 6 days . find the number of men originally employed ?

Output: 4.5


Input: Consider Input: Problem: a car traveled 560 miles per tankful of gasoline on the highway and 336 miles per tankful of gasoline in the city . if the car traveled 6 fewer miles per gallon in the city than on the highway , how many miles per gallon did the car travel in the city ?

Output: 9


Input: Consider Input: Problem: if a - b = 5 and a 2 + b 2 = 31 , find the value of ab .


Output: 3