A runner, jogging along a straight$-$line path, starts at a position $60\mathrm{.}0m$ east of a milestone marker and heads west. After a short time interval he is $34\mathrm{.}7m$ west of the mile marker. Choose east to be the positive $x-$direction.

What is the runner's displacement from his starting point? Enter a positive value if the displacement is toward east of the milestone and a negative value if the displacement is toward west of the milestone.