The ornamental design for a lamp, as shown and described.
FIG. 1 is a perspective view of an embodiment of the ornamental design of the lamp.
FIG. 2 is a top view of an embodiment of the ornamental design of the lamp.
FIG. 3 is a side view of an embodiment of the ornamental design of the lamp.
FIG. 4 is a front/back view of an embodiment of the ornamental design of the lamp.
FIG. 5 is a bottom view of an embodiment of the ornamental design of the lamp.
FIG. 6 is another perspective view of an embodiment of the ornamental design of the lamp.
FIG. 7 is another top view of an embodiment of the ornamental design of the lamp.
FIG. 8 is another perspective view of an embodiment of the ornamental design of the lamp; and,
FIG. 9 is another top view of an embodiment of the ornamental design of the lamp.
The broken-line disclosure in the views is understood to represent portions of the article in which the claimed design is embodied, but which form no part of the claimed design.