The ornamental design for a chair, as shown and described.
FIG. 1 is a perspective front view of a chair according to my design;
FIG. 2 is a side view of the chair according to my design; both sides of
the chair being the same;
FIG. 3 is a rear view of the chair shown in FIG. 1;
FIG. 4 is a top view of the chair according to FIG. 1 but on a reduced
scale, the schematically shown back thereof having the same appearance as
in FIG. 1.
FIG. 5 is a bottom view of the chair according to FIG. 1 but on a reduced
scale, the schematically shown back thereof having the same appearance as
in FIG. 1.