The ornamental design for a football, as shown and described.
FIG. 1 is a top perspective view of a football showing my new design;
FIG. 2 is a bottom perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a right end elevational view thereof;
FIG. 6 is a left end elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines are included for the purpose of illustrating portions of the football, namely the end caps, skeletal struts and lacing that form no part of the claimed design.