The ornamental design for a pair of boots, as shown and described.
FIG. 1 is a perspective view of a pair of boots showing the left shoe version of my design with the right shoe as a mirror image thereof.
FIG. 2 is a side elevation view thereof;
FIG. 3 is an opposite side elevation view thereof;
FIG. 4 is a front elevation view thereof; and,
FIG. 5 is a top view thereof.
The broken lines in the drawings represent unclaimed environment and form no part of the claim. The left shoe of the design is shown, with a right shoe as a mirror image thereof.