The ornamental design for an ottoman, as shown and described.
FIG. 1 is a perspective view of the ottoman with an unclaimed cushion.
FIG. 2 is a perspective view of the ottoman without the unclaimed cushion.
FIG. 3 is a front elevational view of the ottoman of FIG. 2.
FIG. 4 is a rear elevational view of the ottoman of FIG. 2.
FIG. 5 is a left side view of the ottoman of FIG. 2.
FIG. 6 is a right side view of the ottoman of FIG. 2.
FIG. 7 is a top view of the ottoman of FIG. 2; and,
FIG. 8 is a bottom view of the ottoman of FIG. 2.
The dashed lines of FIGS. 1, 3, 4, 5, 6 and 8 show environmental features that form no part of the claimed design. The woven pattern partially shown on the sides and interior of the ottoman is continuous throughout.