The ornamental design for a coordinate inputinstrument, as shown and described.
FIG. 1 is a bottom-front-right perspective view of a coordinate input instrument according to my new design;
FIG. 2 is a top-rear-left perspective view thereof;
FIG. 3 is a front elevational view thereof, wherein a rear elevational view, a right side elevational view, and a left side elevational view are identical to the front elevational view;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is an enlarged bottom plan view thereof; and,