I claim the ornamental design for a bin, as shown and described.
FIG. 1 is a front/right/top perspective view of a bin (a front/left/top perspective view would be a mirror image thereof);
FIG. 2 is a rear/left/bottom perspective view thereof (a rear/right/bottom perspective view would be a mirror image thereof);
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design, and other broken lines depict portions of the bin that form no part of the claimed design.