The ornamental design for a chair, as shown and described.
FIG. 1 is a perspective view of a chair showing our new design; FIG. 2 is a
top plan view thereof; FIG. 3 is a front elevational view thereof; and,
FIG. 4 is a right side elevational view thereof, the left side view being
a mirror image of that shown. The bottom and rear surfaces of the chair
are not part of the design sought to be patented and are therefore not
shown. The portion of the chair shown in broken lines is not part of the
design sought to be patented.