The ornamental design for a diaper, as shown and described.
FIG. 1 is a perspective view of a diaper, showing my new design in use
condition, the broken line showing of the baby is for illustrative
purposes only and forms no part of the claimed design;
FIG. 2 is a front interior view thereof;
FIG. 3 is a rear exterior view thereof;
FIG. 4 is a side elevational view there, the opposite side elevational view
being identical thereto; and,
FIG. 5 is a bottom plan view thereof, the top plan view being identical
thereto.