Jordan Spieth won the 2015 Masters Golf Tournament with a total score that was 18 under par, and Zach Johnson won the 2007 tournament with a total score that was 1 above par. Using -18 to represent 18 below par and +1 to represent 1 over par, find the difference between these scores (in either order) and take the absolute value of this difference. What does this final number represent?