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

Ex Input:
Problem: company x provides bottled water to its employees in 10 liter bottles , $ 2 each . at least how many 10 l bottles must company x buy monthly , so that new contract with $ 50 fixed monthly rate and $ 1 for 50 l bottle each paid off ? ( assume that no other costs apply )

Ex Output:
28


Ex Input:
Problem: audrey 4 hours to complete a certain job . ferris can do the same job in 3 hours . audrey and ferris decided to collaborate on the job , working at their respective rates . while audrey worked continuously , ferris took 5 breaks of equal length . if the two completed the job together in 2 hours , how many minutes long was each of ferris ’ breaks ?

Ex Output:
6


Ex Input:
Problem: the hcf of two numbers is 42 and the other two factors of their lcm are 11 and 12 . what is the largest number .

Ex Output:

504