The ornamental design for a lamp, as shown and described.
FIG. 1 is a perspective view of a lamp embodying the design of the present
invention.
FIG. 2 is a front side elevational view of the lamp illustrated in FIG. 1,
the back side elevational view, left side elevational view and right side
elevational view being identical thereto.
FIG. 3 is a top view of the lamp of FIG. 1; and,
FIG. 4 is a bottom view of the lamp of FIG. 1.
The lamp shade shown in broken lines does not form a part of the claimed
design.