The ornamental design for a set of pantyhose, as shown and described.
FIG. 1 is a perspective front view of a set of panty hose, including a first leg portion, a second leg portion, and a third leg portion, showing my new design;
FIG. 2 is a front side view thereof;
FIG. 3 is a back side view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top side view thereof; and,
FIG. 7 is a bottom side view thereof.
The dashed lines indicate boundary areas and form no part of the claimed design.