I claim the ornamental design for a football, as shown and described.
FIG. 1 is a top and side perspective view of a football showing my new design;
FIG. 2 is a top view of the football of FIG. 1;
FIG. 3 is a side view of the football of FIG. 1;
FIG. 4 is an end view of the football of FIG. 1; and,
FIG. 5 is a bottom view of the football of FIG. 1.
The broken (dashed) lines are included for the purpose of illustrating the groove portions of the football contour and superficial features that form no part of the claimed design, it being understood that the surface contour underlying said superficial features is part of the claim.