The ornamental design for a ottoman, as shown and described.
FIG. 1 is a perspective view of the ottoman of my design;
FIG. 2 is a side view of the ottoman (the three other side views are mirror
images of this view and are not shown);
FIG. 3 is top view of the ottoman; and,
FIG. 4 is a perspective view of a second embodiment of the ottoman (the
second embodiment being the same as the first embodiment except including
16 button like elements rather than 8).
The bottom of the design for both the first embodiment and the second
embodiment is flat and unornamented.