Write a method that figures out what 'jump' is needed get the given 'sum'. The 'sum' must be the sum of all the integers starting at 'first' going up to and possibly including 'max' (but without going over) by going up by 'jump' each time. For example, if 'first' is 8, 'max' is 22, and 'sum' is 56 you will return a 4. The reason is that 8+12+16+20=56, so you can get the 'sum' of 56 by going up by 4 each time. Preconditions: All parameters are positive. It will be possible to find a value for 'jump' to get the given 'sum' from the other given information.